Comprehensive Income (Detail) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Comprehensive Income (Loss) [Line Items]
Net income:	$ 32,223	$ 20,113	$ 61,414	$ 39,516
Other comprehensive loss, net of tax effect:
Foreign currency translation adjustments	672	(3,789)	1,524	(6,329)
Unrealized (loss) gain on interest rate swaps	(2,563)	906	(1,732)	1,584
Amortization of pension unrealized gain	(34)	(54)	(67)	(113)
Other comprehensive loss	(1,925)	(2,937)	(275)	(4,858)
Comprehensive income	$ 30,298	$ 17,176	$ 61,139	$ 34,658