Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - 9 months ended Sep. 30, 2017 - USD ($) $ in Thousands	2007 Incentive Plan [Member] Common Stock [Member] Common Class A [Member]	2007 Incentive Plan [Member] Common Stock [Member]	2007 Incentive Plan [Member] Treasury Stock [Member] Common Class A [Member]	2007 Incentive Plan [Member] Treasury Stock [Member]	2007 Incentive Plan [Member]	2017 Equity and Incentive Compensation Plan [Member] Common Stock [Member] Common Class A [Member]	2017 Equity and Incentive Compensation Plan [Member]	Common Stock [Member] Common Class A [Member]	Common Stock [Member]	Retained Earnings [Member]	Treasury Stock [Member] Common Class A [Member]	Treasury Stock [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2016								8,073,993	71,229,497		(1,669,131)	(5,135,406)
Balance at Dec. 31, 2016								$ 21,764	$ 658,135	$ (101,365)	$ (23,340)	$ (44,688)	$ (17,645)	$ 492,861
Net income										96,382				96,382
401(k) plan (in shares)									1,224
401(k) plan									$ 16					16
Issuance of restricted stock (in shares)	198,220	307,943	(81,561)	(77,632)		76,856
Issuance of restricted stock			$ (892)	$ (874)	$ (1,766)
Repurchase of common stock (in shares)												(322,038)
Repurchase of common stock												$ (4,000)		(4,000)
Share-based compensation								$ 2,077	$ 2,226					4,303
Balance (in shares) at Sep. 30, 2017								8,349,069	71,538,664		(1,750,692)	(5,535,076)
Balance at Sep. 30, 2017								$ 23,841	$ 660,377	(3,876)	$ (24,232)	$ (49,562)	$ (17,645)	588,903
Adoption of ASU 2016-09 excess tax benefit for stock-based compensation										$ 1,107				$ 1,107