Leases - Gross Carrying Value by Major Asset Class and Accumulated Depreciation (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Capital Leased Assets [Line Items]
Total assets recorded under capital leases	$ 2,312	$ 2,312
Less: accumulated depreciation	(882)	(464)
Net assets recorded under capital leases	1,430	1,848
Building and leasehold improvements [Member]
Capital Leased Assets [Line Items]
Total assets recorded under capital leases	2,117	2,117
Furniture, fixtures and other equipment [Member]
Capital Leased Assets [Line Items]
Total assets recorded under capital leases	$ 195	$ 195