Loans Receivable and Allowance for Loan Losses (Details 8) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Recorded Investment
Total	$ 13,155,914	$ 13,197,560
Residential Mortgage Loans | Interest-only loans
Recorded Investment
Total	3,006,691
Residential Mortgage Loans | Interest-only loans | Within one year
Recorded Investment
Total	194,654
Residential Mortgage Loans | Interest-only loans | More than one year to three years
Recorded Investment
Total	1,268,856
Residential Mortgage Loans | Interest-only loans | More than three years to five years
Recorded Investment
Total	1,274,755
Residential Mortgage Loans | Interest-only loans | Over five years
Recorded Investment
Total	$ 268,426