Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 2,270	$ 5,284
Other comprehensive income (loss), net of tax:
Change in fair value of interest rate swap agreements	(632)	(1,170)
Total other comprehensive income (loss)	(632)	(1,170)
Comprehensive income	$ 1,638	$ 4,114