Quantitative inputs level 3 (Detail) (USD $) In Thousands, unless otherwise specified											6 Months Ended									6 Months Ended			6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2013 Fair Value, Measurements, Recurring [Member]	Dec. 31, 2012 Fair Value, Measurements, Recurring [Member]	Jun. 30, 2013 Fair Value, Measurements, Nonrecurring [Member]		Jun. 30, 2012 Fair Value, Measurements, Nonrecurring [Member]		Jun. 30, 2013 Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Contingent Liability [Member] Fair Value Inputs Level 3 Internal Valuation Technique [Member] Fair Value, Measurements, Recurring [Member]	Jun. 30, 2013 Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Contingent Liability [Member] Fair Value Inputs Level 3 Internal Valuation Technique [Member] Fair Value, Measurements, Recurring [Member] Risk Premium [Member]	Jun. 30, 2013 Servicing Asset At Fair Value Amount [Member] Fair Value Inputs Level 3 Internal Valuation Technique [Member] Fair Value, Measurements, Recurring [Member]	Jun. 30, 2013 Loan Fair Value Inputs Level 3 Internal Valuation Technique [Member] Fair Value, Measurements, Nonrecurring [Member]		Jun. 30, 2013 Real Estate Acquired in Satisfaction of Debt [Member] Fair Value Inputs Level 3 Internal Valuation Technique [Member] Fair Value, Measurements, Nonrecurring [Member]		Jun. 30, 2013 Collateralized Mortgage Obligations Member Fair Value, Measurements, Recurring [Member]	Dec. 31, 2012 Collateralized Mortgage Obligations Member Fair Value, Measurements, Recurring [Member]	Jun. 30, 2013 Collateralized Mortgage Obligations Member Trading Account Assets[Member] Fair Value Inputs Level 3 Internal Valuation Technique [Member] Fair Value, Measurements, Recurring [Member]	Jun. 30, 2013 Other Securities [Member] Fair Value, Measurements, Recurring [Member]	Dec. 31, 2012 Other Securities [Member] Fair Value, Measurements, Recurring [Member]	Jun. 30, 2013 Other Securities [Member] Trading Account Assets[Member] Fair Value Inputs Level 3 Internal Valuation Technique [Member] Fair Value, Measurements, Recurring [Member]
Assets, Fair Value Disclosure [Abstract]
Trading Account Assets Fair Value Disclosure					$ 293,829	$ 314,515												$ 2,137	$ 3,117	$ 1,653	$ 21,773	$ 23,734	$ 1,006
Servicing Asset At Fair Value Amount	153,444	154,430	155,711	151,323	153,444	154,430							153,444
Loans Receivable, Fair Value Disclosure							40,801	[1]	24,151	[1]				36,330	[2]
Real Estate Acquired Through Foreclosure							59,193	[3]	87,185	[4]						30,406	[5]
Liabilities, Fair Value Disclosure [Abstract]
Business Acquisition, Contingent Consideration, at Fair Value					$ (119,253)	$ (112,002)					$ (119,253)
Fair Value Inputs [Abstract]
Fair Value Measurements, Valuation Techniques											cash flow model Discounted		model Discounted cash flow	Appraisal External		Appraisal External				model Discounted cash flow			cash flow Discounted model
Unobservable Inputs											Credit loss rate on covered loans of discount rate Risk premium component		Prepayment speed Weighted average life Discount rate	Haircut applied on external appraisals		Haircut applied on external appraisals				Weighted average life Yield Constant prepayment rate			Weighted average life Yield Constant prepayment rate
Fair Value Inputs Quantitative Information [Abstract]
Fair Value Inputs Weighted Average Life And Range													11.2 years (4.0 - 18.7 years)							2.4 years (0.1 - 5.3 years)			5.6
Fair Value Inputs Prepayment Rate																							10.80%
Fair Value Inputs Prepayment Weighted Average And Range													8.9% (5.4% - 25.1%)							26.3% (23.0% - 27.6%)
Fair Value Inputs Yield																				4.1% (0.4% - 4.7%)			12.2
Fair Value Inputs Credit Loss Rate											17.7% (0.0% - 100.0%)
Fair Value Inputs Discount Rate Weighted Average And Range												4.4	11.9% (10.0% - 15.5%)
Fair Value Inputs Haircut External Appraisal														20.5% (10.0% - 38.3%)		28.4% (12.0% - 40.0%)

[1] Relates mostly to certain impaired collateral dependent loans. The impairment was measured based on the fair value of the collateral, which is derived from appraisals that take into consideration prices in observed transactions involving similar assets in similar locations, in accordance with the provisions of ASC Section 310-10-35.

[2] Loans held-in-portfolio in which haircuts were not applied to external appraisals were excluded from this table.

[3] Represents the fair value of foreclosed real estate and other collateral owned that were written down to their fair value. Costs to sell excluded from the reported fair value amount were $3 million at June 30, 2013.

[4] Represents the fair value of foreclosed real estate and other collateral owned that were written down to their fair value. Costs to sell excluded from the reported fair value amount were $5 million at June 30, 2012.

[5] Other real estate owned in which haircuts were not applied to external appraisals were excluded from this table.