Annual report pursuant to Section 13 and 15(d)

Nature of Operations and Summary of Significant Accounting Policies - Basic and Diluted Income Per Share (Details)

v3.7.0.1
Nature of Operations and Summary of Significant Accounting Policies - Basic and Diluted Income Per Share (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2016
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Schedule of Earnings Per Share, Basic and Diluted, by Common Class, Including Two Class Method [Line Items]        
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount   345    
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount $ 19,800      
Basic EPS:        
Net income available to common stockholders   $ 55,086 $ 47,241 $ 20,360
Less: undistributed earnings to participating securities     $ 0 $ 127
Net income allocated to common stockholders (in shares)   11,382,000 12,302,000 12,131,000
Net income allocated to common stockholders (in dollars per share)   $ 4.84 $ 3.84 $ 1.67
Effect of dilutive securities:        
Warrants to purchase common stock (in shares)   0 21,000 421,000
Non-vested restricted stock (in shares)   25,000 49,000 48,000
Plus: reallocation of undistributed earnings to participating securities     $ 0 $ 5
Diluted EPS:        
Net income allocated to common stockholders plus assumed conversions   $ 55,086 $ 47,241 $ 20,238
Net income allocated to common stockholders plus assumed conversions (in shares)   11,407,000 12,372,000 12,600,000
Net income allocated to common stockholders plus assumed conversions (in dollars per share)   $ 4.83 $ 3.82 $ 1.61
Distributed        
Basic EPS:        
Net income available to common stockholders   $ 55,086 $ 47,241 $ 20,233