Debt (Detail) - Borrowings (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Amount outstanding	$ 200,000		$ 200,000
Bank Term Loan [Member]
Amount outstanding	157,500	[1]	180,000	[1]
Contractual annualized interest rate	1.86%	[1]
Revolver [Member]
Amount outstanding	$ 42,500	[1],[2]	$ 20,000	[1],[2]
Contractual annualized interest rate	1.86%	[1],[2]

[1] The term and revolver contractual rates consisted of a 0.36%, three-month floating Eurodollar base rate plus a margin of 1.50%. However, the Company has an interest rate swap contract which converts the floating Eurodollar base rates to a fixed base rate on $200.0 million of borrowings (see below). As a result, the effective annual interest rate on the total debt outstanding under the 2010 Credit Facility, including the effect of the swap, was 3.76% as of September 30, 2012 and December 31, 2011.

[2] The Company had $354.2 million of additional borrowing capacity on the revolver (not including the expansion feature) as of September 30, 2012.