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, 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        
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)      
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 (unaudited) at Mar. 31, 2014 4,986,787 4,238,684 67,484 680,606 (1,895) 1,908
Ending balance, shares (unaudited) at Mar. 31, 2014   206,854,499        
Beginning balance, amount at Dec. 31, 2014 5,279,107 4,264,764 74,071 934,454 (1,310) 7,128
Beginning balance, shares at Dec. 31, 2014 207,493,541 207,493,541        
Activities during the period (unaudited) [Roll Forward]            
Net income 99,554     86,693   12,861
Exercise of stock options, shares   950        
Exercise of stock options, amount 28 40 (12)      
Vesting of restricted stock units, shares   517,768        
Vesting of restricted stock units, amount 0 25,463 (25,463)      
Tax benefit on options exercised 1,916   1,916      
Stock-based compensation 8,789   8,789      
Distributions to non-controlling interest (12,087)         (12,087)
Other comprehensive income, net of tax 276       276  
Other (28)   (28)      
Ending balance, amount (unaudited) at Mar. 31, 2015 $ 5,377,555 $ 4,290,267 $ 59,273 $ 1,021,147 $ (1,034) $ 7,902
Ending balance, shares (unaudited) at Mar. 31, 2015 208,012,259 208,012,259