Income Before Provision for Income Taxes (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income before income tax expense:
Domestic									$ 9,291	$ 2,872	$ 809
Foreign									56,572	49,920	30,286
Income before provision for income taxes	19,040	16,587	15,896	14,340	15,349	14,975	10,603	11,865	65,863	52,792	31,095
Current
Federal									6,881	4,878	2,918
State									319	389	160
Foreign									7,969	2,483	2,573
Deferred
Federal									(625)	(1,629)	(1,016)
State									24	(72)	(76)
Foreign									(3,189)	2,390	(1,772)
Income tax expense	$ 4,041	$ 2,522	$ 2,575	$ 2,241	$ 2,965	$ 1,025	$ 2,326	$ 2,123	$ 11,379	$ 8,439	$ 2,787