CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Comprehensive income:
Net income	$ 12,022	$ 10,544	$ 36,257	$ 30,229
Derivative instruments:
Reclassification of losses to net income, net of tax of $12, $14, $25 and $26, respectively	19	18	37	37
Other comprehensive income	19	18	37	37
Comprehensive income	$ 12,041	$ 10,562	$ 36,294	$ 30,266