CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Unrealized gains on available-for-sale securities, taxes	$ 214	$ 0	$ 183
Reclassification adjustment for gains on available-for-sale securities included in net income, taxes	0	0	508
Foreign current translation adjustments, tax benefit	16,800	0	0
Unfunded pension liability, taxes	$ 57	$ 7	$ 248