Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - 6 months ended Jun. 30, 2016 - USD ($)	401(k) Plan [Member] Common Stock [Member]	401(k) 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, 2015			7,855,381	70,989,426		(1,611,371)	(4,882,705)
Balance at Dec. 31, 2015			$ 19,325,000	$ 655,446,000	$ (163,638,000)	$ (22,685,000)	$ (41,890,000)	$ (17,284,000)	$ 429,274,000
Net income					26,652,000				26,652,000
401(k) plan (in shares)	1,097
401(k) plan	$ 14,000	$ 14,000				$ (655,000)	$ (798,000)		(1,453,000)
Restricted stock awards (in shares)			218,612	237,500		(57,760)	(60,518)
Restricted stock awards	$ 14,000	$ 14,000				$ (655,000)	$ (798,000)		(1,453,000)
Amortization of restricted stock and stock option awards			$ 1,210,000	$ 1,346,000					2,556,000
Balance (in shares) at Jun. 30, 2016			8,073,993	71,228,023		(1,669,131)	(4,943,223)
Balance at Jun. 30, 2016			$ 20,535,000	$ 656,806,000	$ (136,986,000)	$ (23,340,000)	$ (42,688,000)	$ (17,284,000)	$ 457,043,000