Stockholders Equity - Additional Information (Detail) (USD $)
 1 Months Ended 3 Months Ended 12 Months Ended 0 Months Ended 1 Months Ended 12 Months Ended
Apr. 30, 2014
Aug. 31, 2012
Oct. 31, 2014
Jul. 31, 2014
Apr. 30, 2014
Jan. 31, 2014
Dec. 31, 2012
Oct. 31, 2012
Aug. 31, 2012
Jul. 31, 2012
Apr. 30, 2012
Jan. 31, 2012
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Feb. 28, 2015
Jan. 31, 2015
Dec. 31, 2012
Dec. 31, 2011
Jan. 01, 2014
Jan. 01, 2015
Nov. 30, 2014
Nov. 30, 2006
Shareholders Equity And Share Based Payments [Line Items]                                              
Preferred stock, shares authorized                         1,000,000                    
Common stock, shares authorized                         137,500,000 137,500,000                  
Preferred stock, par value                         $ 0.01                    
Proceeds from sale of stock $ 32,500,000                       $ 32,527,000                    
Treasury stock acquired, value                         2,505,000 119,000 1,651,000                
Cash Dividend per share declared     $ 0.020 $ 0.020 $ 0.020 $ 0.020 $ 0.140 $ 0.035 $ 0.015 $ 0.020 $ 0.020 $ 0.020                      
Dividends paid per share                         $ 0.08   $ 0.25                
Cash dividend paid   566,000                                          
Payment date     Nov. 18, 2014 Aug. 15, 2014 May 15, 2014 Feb. 18, 2014 Dec. 31, 2012 Nov. 15, 2012 Aug. 31, 2012 Aug. 15, 2012 May 15, 2012 Feb. 15, 2012                      
Date of record     Nov. 07, 2014 Aug. 05, 2014 May 05, 2014 Feb. 07, 2014 Dec. 18, 2012 Nov. 02, 2012 Aug. 16, 2012 Aug. 03, 2012 May 04, 2014 Feb. 03, 2012                      
Dividend paid     857,000 856,000 846,000 771,000 5,300,000 1,300,000 566,000 755,000 743,000 751,000 3,330,000   9,376,000                
Excess tax benefit                         6,600,000 3,000,000                  
Income tax benefit related to stock-based compensation included in net income (loss)                         0 2,600,000 4,700,000                
Options granted, Shares                         1,340,686                    
Stock option compensation not yet recognized                         7,700,000                    
Proceed from exercise of stock option                         4,200,000 2,900,000 27,000                
Income tax benefit (shortfall) of option exercises and restricted stock vesting, net                         1,229,000 384,000 4,006,000                
Repurchase of stock for tax withholding                         175,000 220,000 391,000                
Vesting of restricted shares                         527,000 1,031,000 1,255,000                
Minimum withholding tax                         1,100,000 1,800,000 1,600,000                
Public Offering Two                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Shares sold 3,200,000                                            
Public Offering Two | Underwriters Option To Purchase Units                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Shares sold 343,000                                            
Stock Options                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Unrecognized compensation cost, weighted average recognition period                         2 years                    
Excess Tax Benefits from Stock Based Compensation Expense                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Income tax benefit (shortfall) of option exercises and restricted stock vesting, net                           76,000                  
Restricted Stock                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Unrecognized compensation cost, weighted average recognition period                         2 years                    
Unrecognized compensation expense                         10,000,000                    
Vesting of restricted shares                         1,150,319                    
Vesting of restricted shares                         698,992                    
Service and market based awards                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Options granted, Shares                         0                    
Subsequent Event                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Cash Dividend per share declared                                 $ 0.02            
Payment date                                 Feb. 17, 2015            
Date of record                                 Feb. 06, 2015            
Dividend payable                                 839,000            
Options vested                               139,000              
Vesting of restricted shares                               108,000              
Stock Incentive Plan 2003                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock incentive plan, annual increase as a percentage of outstanding common stock                         5.00%                    
Stock Incentive Plan 2003 | Maximum                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock incentive plan, shares authorized                         8,000,000                    
Stock Incentive Plan 2003 | Stock Options                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock incentive plan, shares authorized                         4,000,000                    
Stock Incentive Plan Twenty Twelve                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock incentive plan, annual increase as a percentage of outstanding common stock                             5.00%                
Stock incentive plan, options term                             10 years                
Stock incentive plan, options annual vesting percentage             25.00%               25.00%     25.00%          
Stock incentive plan, vesting period                             4 years                
Stock Incentive Plan Twenty Twelve | Minimum                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock incentive plan, shares authorized                                       1,924,511      
Stock Incentive Plan Twenty Twelve | Maximum                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock incentive plan, shares authorized                                       7,301,899      
Stock Incentive Plan Twenty Twelve | Stock Options | Maximum                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock incentive plan, shares authorized             3,500,000               3,500,000     3,500,000          
Stock Incentive Plan Twenty Twelve | Restricted Stock Units                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock incentive plan, vesting period                             4 years                
Stock incentive plan, stock grants annual vesting percentage                             25.00%                
Stock Incentive Plan Twenty Twelve | Subsequent Event | Minimum                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock incentive plan, shares authorized                                         2,102,493    
Stock Incentive Plan Twenty Twelve | Subsequent Event | Maximum                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock incentive plan, shares authorized                                         9,404,392    
Employee Stock Purchase Plan, Twenty Zero Four                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock incentive plan, shares authorized                         300,000                    
Employee Stock Purchase Plan Twenty Fourteen                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock incentive plan, shares authorized                         225,000                    
Stock purchased by eligible employee                         11,944                    
Percentage of compensation eligible for purchase of stock                         15.00%                    
Maximum value of stock employee is permitted to purchase in any calendar year                         25,000                    
Employee Stock Purchase Plan Twenty Fourteen | Minimum                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock purchased by eligible employee, price per share                         $ 3.94                    
Employee Stock Purchase Plan Twenty Fourteen | Maximum                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock purchased by eligible employee, price per share                         $ 11.42                    
Fiscal Year 2013                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Cash Dividend per share declared                                   $ 0.14          
Payment date                                   Dec. 31, 2012          
Date of record                                   Dec. 18, 2012          
Dividend paid                                   5,300,000          
Class B                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Common stock, shares authorized                         125,000,000 125,000,000                  
Votes per share                         1                    
Number of additional shares authorized to be repurchased                         0                    
Treasury stock acquired, shares                         669,000 31,000 387,000                
Treasury stock acquired, value                         $ 2,500,000 $ 119,000 $ 1,700,000                
Number of shares authorized to be repurchased                                           3,000,000  
Treasury stock, shares retired                         598,000 679,000                  
Cash Dividend per share declared   $ 0.035               $ 0.02                          
Dividends paid per share   $ 0.015                                          
Class B | Public Offering One                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Shares sold 3,400,000                                            
Class B | Public Offering One | Underwriters Option To Purchase Units                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Shares sold 514,100                                            
Shares sold, price per share $ 10.50       $ 10.50                                    
Class B | Minimum                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Number of additional shares authorized to be repurchased                                             3,000,000
Class B | Maximum                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Number of additional shares authorized to be repurchased                                             13,000,000
Class B | Employee Stock Purchase Plan, Twenty Zero Four                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Common stock purchase price as a percentage of fair value                         95.00%                    
Stock purchased by eligible employee                           11,511 9,817       3,637        
Class B | Employee Stock Purchase Plan, Twenty Zero Four | Minimum                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock purchased by eligible employee, price per share                           $ 4.00 $ 3.43       5.94        
Class B | Employee Stock Purchase Plan, Twenty Zero Four | Maximum                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Stock purchased by eligible employee, price per share                           $ 8.22 $ 4.24       8.44        
Class B | Employee Stock Purchase Plan Twenty Fourteen                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Common stock purchase price as a percentage of fair value                         95.00%                    
Class A                                              
Shareholders Equity And Share Based Payments [Line Items]                                              
Common stock, shares authorized                         12,500,000 12,500,000                  
Votes per share                         25                    
Cash Dividend per share declared   $ 0.035               $ 0.02                          
Dividends paid per share   $ 0.015