Loans that were Considered Impaired Based on ASC Section 310-10-35 (Detail) (Non Covered Loans, USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Financing Receivable, Impaired [Line Items]
Impaired loans	$ 895,305	$ 1,739,072	$ 895,305	$ 1,739,072	$ 798,499
Allowance for impaired loans	20,806	383,439	20,806	383,439	13,770
Average balance of impaired loans	860,127	1,747,025	839,584	1,236,004
Interest income recognized on impaired loans	3,708	4,769	7,056	9,232
Impaired Loans - With an Allowance
Financing Receivable, Impaired [Line Items]
Impaired loans	226,681	1,349,536	226,681	1,349,536	154,349
Allowance for impaired loans	20,806		20,806		13,770
Impaired Loans - With No Allowance
Financing Receivable, Impaired [Line Items]
Impaired loans	$ 668,624	$ 389,536	$ 668,624	$ 389,536	$ 644,150