Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (17,416)	$ 3,933	$ 18,343
Other comprehensive income (loss), net of tax
Change in unrealized income with realized income on the Statements of Operations	0	38	(18)
Total other comprehensive income (loss), net of tax	0	38	(18)
Comprehensive income (loss)	$ (17,416)	$ 3,971	$ 18,325