Future Minimum Lease Commitments Under Non-Cancelable Operating Leases (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011
Operating Leased Assets [Line Items]
Minimum lease payments	$ 101,062
Minimum sublease rentals	(1,172)
Net future minimum lease commitments	99,890
One Year from Balance Sheet Date
Operating Leased Assets [Line Items]
Minimum lease payments	25,961
Minimum sublease rentals	(280)
Net future minimum lease commitments	25,681
More than One and within Two Years from Balance Sheet Date
Operating Leased Assets [Line Items]
Minimum lease payments	19,343
Minimum sublease rentals	(283)
Net future minimum lease commitments	19,060
More than Two and within Three Years from Balance Sheet Date
Operating Leased Assets [Line Items]
Minimum lease payments	15,944
Minimum sublease rentals	(285)
Net future minimum lease commitments	15,659
More than Three and within Four Years from Balance Sheet Date
Operating Leased Assets [Line Items]
Minimum lease payments	12,689
Minimum sublease rentals	(118)
Net future minimum lease commitments	12,571
More than Four and within Five Years from Balance Sheet Date
Operating Leased Assets [Line Items]
Minimum lease payments	10,331
Minimum sublease rentals	(103)
Net future minimum lease commitments	10,228
More than Five Years from Balance Sheet Date and Thereafter
Operating Leased Assets [Line Items]
Minimum lease payments	16,794
Minimum sublease rentals	(103)
Net future minimum lease commitments	$ 16,691