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)	$ (72,788)	$ (26,938)	$ 62,042
Other comprehensive income (loss):
Change in fair value of interest rate swaps	0	0	(137)
Net loss reclassified into income on settlement of interest rate swaps	0	119	1,056
Other comprehensive income	0	119	919
Total comprehensive income (loss)	$ (72,788)	$ (26,819)	$ 62,961