CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 30,839	$ (152,061)	$ (43,484)	$ (202,688)
Other comprehensive (loss) income:
Holding gains (losses) arising during period, net of tax	134	(4)	(253)	201
Total comprehensive income (loss)	$ 30,973	$ (152,065)	$ (43,737)	$ (202,487)