Consolidated Statements of Equity (USD $)
In Thousands, except Share data, unless otherwise specified
Total
Common Stock
Additional Paid-in Capital
Retained Earnings
Accumulated Other Comprehensive Income
Noncontrolling Interest
Beginning balance, amount at Dec. 31, 2012 $ 4,609,861 $ 4,180,778 $ 73,530 $ 354,991 $ (2,191) $ 2,753
Beginning balance, shares at Dec. 31, 2012   205,399,102        
Activities during the period (unaudited) [Roll Forward]            
Net income 56,784     51,408   5,376
Exercise of stock options, shares   133,264        
Exercise of stock options, amount 785 1,125 (340)      
Vesting of restricted stock units, shares   373,018        
Vesting of restricted stock units, amount 0 20,898 (20,898)      
Tax benefit on options exercised 4,928   4,928      
Stock-based compensation 6,644   6,644      
Distribution declared to non-controlling interest 2,114         2,114
Other comprehensive income, net of tax 261       261  
Ending balance, amount at Mar. 31, 2013 4,677,149 4,202,801 63,864 406,399 (1,930) 6,015
Ending balance, shares at Mar. 31, 2013   205,905,384        
Beginning balance, amount at Dec. 31, 2013 4,911,498 4,215,291 77,790 617,161 (1,752) 3,008
Beginning balance, shares at Dec. 31, 2013 206,305,070 206,305,070        
Activities during the period (unaudited) [Roll Forward]            
Net income 77,345     63,445   13,900
Exercise of stock options, shares   139,800        
Exercise of stock options, amount 3,567 5,070 (1,503)      
Warrants exercised, shares   0        
Warrants exercised, amount 0 0 0      
Vesting of restricted stock units, shares   409,629        
Vesting of restricted stock units, amount 0 18,323 (18,323)      
Tax benefit on options exercised 2,692   2,692      
Stock-based compensation 6,828   6,828      
Distributions to non-controlling interest (15,000)         (15,000)
Other comprehensive income, net of tax (143)       (143)  
Ending balance, amount at Mar. 31, 2014 $ 4,986,787 $ 4,238,684 $ 67,484 $ 680,606 $ (1,895) $ 1,908
Ending balance, shares at Mar. 31, 2014 206,854,499 206,854,499