CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)
Net income (loss)	$ 34,425	$ 9,294	$ 58,472	$ (9,063)
Other comprehensive income (loss):
Foreign currency translation	105		94
Unrealized gain (loss) on restricted investments and marketable securities, net of tax	(49)	(309)	990	134
Reclassification adjustment for realized loss on marketable securities			178
Defined benefit pension obligation, net of tax	209		209
Other comprehensive income (loss)	265	(309)	1,471	134
Comprehensive income (loss)	$ 34,690	$ 8,985	$ 59,943	$ (8,929)