CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Comprehensive income:
Net income	$ 26,232	$ 20,030	$ 61,011	$ 56,287
Derivative instruments:
Reclassification of losses to net income, net of tax of $13, $12, $37 and $38 for each of the three and nine months ended Sept. 30, 2015 and 2014, respectively	19	20	57	57
Other comprehensive income	19	20	57	57
Comprehensive income	$ 26,251	$ 20,050	$ 61,068	$ 56,344