CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (14,301)	$ 33,824
Unrealized (loss) gain on available-for-sale securities, net of tax	0	2
Comprehensive (loss) income	$ (14,301)	$ 33,826