CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Comprehensive income:
Net income	$ 69,135	$ 74,636	$ 70,642
Derivative instruments:
Reclassification of losses to net income, net of tax of $51 for the years ended Dec. 31, 2016, 2015, and 2014, respectively.	76	76	76
Other comprehensive income	76	76	76
Comprehensive income	$ 69,211	$ 74,712	$ 70,718