CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Net loss	$ (21,035)	$ (82,955)	$ (72,314)
Other comprehensive income (loss), before tax:
Unrealized gain, net arising during the period	0	0	202
Loss reclassified into earnings	0	0	44
Other Comprehensive Income (Loss) before tax, Cash Flow Hedges	0	0	246
Unrealized loss, net arising during the period	0	(658)	(903)
Loss reclassified into earnings	0	384	2,735
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax	0	(274)	1,832
Adjustment to pension benefit plan	202	528	(279)
Unrealized foreign exchange gain (loss), net on intercompany long-term loans arising during the period	667	(1,705)	0
Translation gain (loss) arising during the period	(5,100)	11,471	(4,633)
Loss reclassified into earnings	11	106	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax	(5,089)	11,577	(4,633)
Other comprehensive income (loss) before tax	(4,220)	10,126	(2,834)
Provision for (benefit from) income taxes	378	(526)	18
Other comprehensive income (loss), net of tax	(4,598)	10,652	(2,852)
Total comprehensive loss	$ (25,633)	$ (72,303)	$ (75,166)