CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Comprehensive income:
Net income	$ 17,631	$ 22,267
Derivative instruments:
Reclassification of losses to net income, net of tax of $13 and $13, respectively	19	19
Other comprehensive income	19	19
Comprehensive income	$ 17,650	$ 22,286