Consolidated Statements of Other Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Statements of Other Comprehensive Income (Loss)
Net income (loss)	$ (15,944)	$ 8,378	$ 35,014
Other comprehensive income (loss):
Unrealized gain (loss) on derivative financial instruments	6,688	12,589	(2,863)
Total other comprehensive income (loss)	6,688	12,589	(2,863)
Comprehensive income (loss)	$ (9,256)	$ 20,967	$ 32,151