Condensed Consolidated Statements Of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (11,029)	$ 18,090
Other comprehensive income:
Net unrealized gains on available-for-sale securities, net of tax	38	1,463
Other comprehensive income	38	1,463
Comprehensive income (loss)	$ (10,991)	$ 19,553