XML 64 R53.htm IDEA: XBRL DOCUMENT v3.5.0.2
Stockholders' Equity - Additional Information (Detail) - USD ($)
3 Months Ended 9 Months Ended
Oct. 07, 2016
Sep. 19, 2016
Jun. 08, 2016
Feb. 22, 2016
Jan. 05, 2016
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Dec. 31, 2015
Dec. 31, 2014
Stockholders Equity [Line Items]                      
Common stock, shares issued           91,849,408   91,849,408   90,320,374  
Unvested shares of common stock           3,443,178   3,443,178      
Treasury stock, shares           6,519,773   6,519,773   6,519,773  
Cash dividends declared per share   $ 0.10 $ 0.21 $ 0.21 $ 0.21 $ 0.10 $ 0.21 $ 0.73 $ 0.84    
Cash dividends payable date   Oct. 07, 2016 Jul. 01, 2016 Apr. 01, 2016 Jan. 22, 2016            
Dividends paid to stockholders               $ 56,756,000 $ 54,370,000    
Dividends payable           $ 9,467,000 $ 18,396,000 $ 9,467,000 $ 18,396,000 $ 430,000  
Share Repurchase Program, authorized amount                     $ 250,000,000
Stock Repurchase Program, number of shares repurchased           0   0      
Treasury stock at cost           $ 154,871,000   $ 154,871,000   $ 154,871,000  
Maximum [Member]                      
Stockholders Equity [Line Items]                      
Share Repurchase Program, remaining authorized repurchase amount           $ 190,000,000   $ 190,000,000      
2.75x Performance Restricted Shares [Member]                      
Stockholders Equity [Line Items]                      
Unvested shares of common stock           1,329,027   1,329,027   1,370,821  
Accumulated dividends on unvested performance restricted shares               $ 3,700,000      
Bonus Performance Restricted Shares [Member]                      
Stockholders Equity [Line Items]                      
Unvested shares of common stock           460,195   460,195   415,995  
Accumulated dividends on unvested performance restricted shares               $ 240,000      
Long-Term Incentive Performance Restricted Shares [Member]                      
Stockholders Equity [Line Items]                      
Unvested shares of common stock           220,288   220,288   62,365  
Accumulated dividends on unvested performance restricted shares               $ 150,000      
Dividends on shares probable of vesting               $ 19,000      
Subsequent Events [Member]                      
Stockholders Equity [Line Items]                      
Dividends paid $ 8,530,000                    
Q3 2016 Declaration [Member]                      
Stockholders Equity [Line Items]                      
Cash dividends declared per share   $ 0.10           $ 0.10      
Cash dividends declared date               Sep. 19, 2016      
Cash dividends payable date               Oct. 07, 2016