Annual report pursuant to Section 13 and 15(d)

Shareholders' Equity, Stock Options and Net Income per Share - Common and Preferred Stock (Details)

v3.6.0.2
Shareholders' Equity, Stock Options and Net Income per Share - Common and Preferred Stock (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
Jul. 21, 2016
Feb. 07, 2014
Mar. 31, 2017
Dec. 31, 2016
Sep. 30, 2016
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
May 31, 2016
Dec. 31, 2008
May 31, 2008
Preferred Stock [Abstract]                      
Preferred stock, shares authorized       5,000,000   5,000,000 5,000,000        
Preferred stock par value per share       $ 0.01   $ 0.01 $ 0.01        
Cash Dividends [Abstract]                      
Quarterly cash dividend per share, common stock     $ 0.15 $ 0.15 $ 0.12   $ 0.12 $ 0.12      
Repurchase of Common Stock [Abstract]                      
Repurchase of common stock (repurchase program)           $ 39,983 $ 19,992 $ 39,972      
Common Stock [Member]                      
Share-based Compensation [Abstract]                      
Number of shares authorized under the plan       7,500,000   7,500,000       4,500,000  
Additional authorized shares for employee stock awards       1,976,119   1,976,119     2,000,000   3,000,000
Minimum [Member] | Employee Stock Option [Member]                      
Share-based Compensation [Abstract]                      
Expected life of options (in years)           7 years          
Option award vesting period           1 year          
Maximum [Member] | Employee Stock Option [Member]                      
Share-based Compensation [Abstract]                      
Expected life of options (in years)           10 years          
Option award vesting period           5 years          
2014 Stock Repurchase Plan [Member] | Common Stock [Member]                      
Repurchase of Common Stock [Abstract]                      
Share repurchase program, authorized shares   2,000,000                  
Stock Repurchased During Period, Shares           676,773 422,404 881,979      
Repurchase of common stock (repurchase program)           $ 29,986 $ 19,992 $ 39,972      
Treasury stock acquired, average cost per share           $ 44.31 $ 47.33 $ 45.32      
2016 Stock Repurchase Plan [Member] | Common Stock [Member]                      
Repurchase of Common Stock [Abstract]                      
Share repurchase program, authorized shares 3,000,000                    
Stock Repurchased During Period, Shares           233,516          
Repurchase of common stock (repurchase program)           $ 9,997          
Treasury stock acquired, average cost per share           $ 42.80          
Remaining shares authorized under share repurchase program           2,766,484