CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement Of Income and Comprehensive Income [Abstract]
Net (loss) income	$ (739)	$ 52,130
Other comprehensive income (loss):
Pension adjustment and reclassification adjustment, net of taxes	173	173
Foreign currency translation	98	(481)
Comprehensive (loss) income	$ (468)	$ 51,822