Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 3,192	$ 5,561	$ (8,912)	$ 15,067
Other comprehensive income (loss):
Pension liability adjustment, net of tax	64	64	128	129
Deferred gain (loss) on cash flow derivatives, net of tax	(47)	44	(45)	155
Other comprehensive income	17	108	83	284
Comprehensive income (loss)	$ 3,209	$ 5,669	$ (8,829)	$ 15,351