Condensed Consolidated Statement of Stockholders' Equity (Unaudited) - 6 months ended Jun. 30, 2015 - USD ($) $ in Thousands	401(k) Plan [Member] Common Stock [Member]	401(k) Plan [Member]	Common Class A [Member] Common Stock [Member] 2007 Incentive Plan [Member]	Common Class A [Member] Common Stock [Member]	Common Class A [Member] Treasury Stock [Member] 2007 Incentive Plan [Member]	Common Class A [Member] Treasury Stock [Member]	Common Stock [Member] 2007 Incentive Plan [Member]	Common Stock [Member]	Retained Earnings [Member]	Treasury Stock [Member] 2007 Incentive Plan [Member]	Treasury Stock [Member]	AOCI Attributable to Parent [Member]	2007 Incentive Plan [Member]	Total
Balance at December 31, 2014 at Dec. 31, 2014				$ 17,096		$ (22,398)		$ 486,317	$ (202,939)		$ (41,072)	$ (20,812)		$ 216,192
Balance at December 31, 2014 (in Shares) at Dec. 31, 2014				7,567,868		(1,578,554)		57,326,180			(4,814,716)
Net income									17,705					17,705
Adjustment to pension liability, net of income tax												7,494		7,494
Issuance of common stock:
Underwritten public offering								$ 167,378						167,378
Underwritten public offering (in Shares)								13,511,040
Issuance of common stock, Employee Benefit Plan	$ 13	$ 13			$ (287)					$ (818)			$ (1,105)
Issuance of common stock, Employee Benefit Plan (in Shares)	1,039		287,513		(32,817)		150,308			(67,989)
Share-based compensation				$ 1,067				$ 935						2,002
Balance at June 30, 2015 at Jun. 30, 2015				$ 18,163		$ (22,685)		$ 654,643	$ (185,234)		$ (41,890)	$ (13,318)		$ 409,679
Balance at June 30, 2015 (in Shares) at Jun. 30, 2015				7,855,381		(1,611,371)		70,988,567			(4,882,705)