Common Stock-Schedule of Earnings per Share, Basic (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Class A Common Stock      
Numerator:      
Allocation of undistributed (loss) earnings $ (32,651) $ 10,408 $ 23,063
Dividends paid 8,573 7,273 5,384
Net (loss) income available to common shareholders, basic $ (24,078) $ 17,681 $ 28,447
Denominator:      
Weighted-average common shares outstanding, basic (in shares) 30,596 30,237 29,853
(Loss) Earnings Per Share - Basic (usd per share) $ (0.79) $ 0.58 $ 0.95
Class B Common Stock      
Numerator:      
Allocation of undistributed (loss) earnings $ (26,348) $ 8,499 $ 19,075
Dividends paid 4,938 4,444 3,456
Net (loss) income available to common shareholders, basic $ (21,410) $ 12,943 $ 22,531
Denominator:      
Weighted-average common shares outstanding, basic (in shares) 24,690 24,690 24,690
(Loss) Earnings Per Share - Basic (usd per share) $ (0.87) $ 0.52 $ 0.91