CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Comprehensive income:
Net income	$ 74,636	$ 70,642	$ 59,468
Derivative instruments:
Reclassification of losses to net income, net of tax of $51 for the years ended Dec. 31, 2015, 2014, and 2013, respectively.	76	76	76
Other comprehensive income	76	76	76
Comprehensive income	$ 74,712	$ 70,718	$ 59,544