CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 65,636	$ 100,739	$ (39,873)
Other comprehensive (loss) income:
Unrealized gains (losses) on available-for-sale securities (net of taxes (benefits) of $105, $152, and ($214), respectively)	77	32	(321)
Unrealized loss on interest rate hedge	(9,579)	0	0
Reclassification adjustment for losses on available-for-sale securities and interest rate hedge included in net income (loss) (net of taxes of $0, $79, and $0, respectively)	806	143	0
Foreign currency translation adjustments (including tax benefits of $5.0 million and $16.8 million in 2018 and 2016, respectively)	(42,350)	41,636	40,728
Unfunded pension liability (net of taxes of $42, $38, and $57, respectively)	82	108	159
Other comprehensive income (loss)	(50,964)	41,919	40,566
Comprehensive income (loss)	$ 14,672	$ 142,658	$ 693