Leases (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Gross carrying value by major asset class and accumulated depreciation
Total assets recorded under capital leases	$ 2,312	$ 2,312
Less: accumulated depreciation	(464)	(54)
Net assets recorded under capital leases	1,848	2,258
Building and leasehold improvements [Member]
Gross carrying value by major asset class and accumulated depreciation
Total assets recorded under capital leases	2,117	2,117
Furniture, fixtures and other equipment [Member]
Gross carrying value by major asset class and accumulated depreciation
Total assets recorded under capital leases	$ 195	$ 195