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	$ 15,787	$ 15,351	$ 43,557	$ 39,182
Other comprehensive income (loss):
Foreign currency translation adjustment	247	(248)	(24)	(257)
Amortization of actuarial loss, net of tax expense of $201, and $151 for the three-month periods ended September 30, 2012, and 2011, respectively; and net of tax expense of $611 and $454 for the nine-month periods ended September 30, 2012, and 2011, respectively.	323	237	963	709
Other comprehensive income (loss):	570	(11)	939	452
Comprehensive income	$ 16,357	$ 15,340	$ 44,496	$ 39,634