Securitizations and Variable Interest Entities ("VIEs") (Narrative) (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012
Securitizations And Variable Interest Entities [Line Items]
Retained interests, VIEs	$ 23,705
Interest-bearing deposits, VIEs	7,537
Aggregate loans balances, VIEs	248,333
Long term-debt, VIEs	239,936
Cumulative-effect adjustment, VIEs	5,805
Adjustment accumulated other comprehensive income	6,922
2006 Transaction [Member]
Securitizations And Variable Interest Entities [Line Items]
Fixed-rate home mortgage loans and variable-rate line of credit loans	349,403
Variable-rate loans	70.50%
Principal balance of loans, percentage	10.00%
2005 Transaction [Member]
Securitizations And Variable Interest Entities [Line Items]
Variable-rate loans	35.40%
Principal balance of loans, percentage	10.00%
Home equity line of credit loans	$ 239,766