Condensed Consolidated Statements of Stockholders' Equity - 3 months ended Mar. 31, 2016 - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance at December 31, 2015 at Dec. 31, 2015	$ 384,167	$ 539	$ (15,845)	$ 194,670	$ 220,974	$ (16,171)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(10,660)				(10,660)
Issuance of common stock (common stock offering at $20 per share, net of issuance costs of $13,798)	186,202	100		186,102
Unrealized gain on derivatives, net of tax	35					35
Unrealized loss on short-term investments, net of tax	(5)					(5)
Pension and post-retirement liability, net of tax	(2,558)					(2,558)
Cash dividend declared ($0.0625 per share)	(3,274)				(3,274)
Equity-based compensation	1,906			1,906
Net tax effect	(343)			(343)
Proceeds from options exercised	22		37	(15)
Shares withheld for employee taxes related to vested restricted stock and stock units	(499)		1,416	(1,915)
Issuance of restricted stock	0		1,069	(1,069)
Balance at March 31, 2016 at Mar. 31, 2016	$ 554,993	$ 639	$ (13,323)	$ 379,336	$ 207,040	$ (18,699)