CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Comprehensive income:
Net income	$ 20,030	$ 22,013	$ 56,287	$ 52,242
Derivative instruments:
Reclassification of losses to net income, net of tax of $12, $12, $38 and $38, respectively	20	20	57	57
Other comprehensive income	20	20	57	57
Comprehensive income	$ 20,050	$ 22,033	$ 56,344	$ 52,299