CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Comprehensive income:
Net income	$ 24,235	$ 19,685
Derivative instruments:
Reclassification of losses to net income, net of tax of $13 for each of the three months ended March 31, 2014 and 2013	18	19
Other comprehensive income	18	19
Comprehensive income	$ 24,253	$ 19,704