Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Net income	$ 44,377	$ 42,302	$ 96,236	$ 85,610
Other Comprehensive Income (loss), net of tax
Amortization of loss on cash flow hedge	(215)	(215)	(646)	(646)
Foreign currency translation adjustment, net	211	(1,167)	191	(164)
Actuarial loss (net of inome tax of $12 and $36 for the three and nine months ended September 30, 2012, respectively)	20	0	60	0
Actuarial pension loss (net of income tax of $6 for the nine months ended September 30, 2011)	0	0	0	(10)
Other comprehensive income (loss), net of tax	446	(952)	897	472
Comprehensive income	$ 44,823	$ 41,350	$ 97,133	$ 86,082