Mortgage Banking Operations (Sensitivity analysis)(Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Key economic assumptions and the sensitivity of the current fair value for single family MSRs
Fair value of single family MSR	$ 136,897	$ 87,396
Single Family Residential [Member]
Key economic assumptions and the sensitivity of the current fair value for single family MSRs
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Weighted Average Life	6 years 10 months 28 days
Constant prepayment rate (1)	11.63%
Impact on fair value of 25 basis points decrease	(6,893)
Impact on fair value of 50 basis points decrease	(14,523)
Discount rate	10.50%
Impact on fair value of 100 basis points increase	(5,314)
Impact on fair value of 200 basis points increase	(10,232)
Fair Value, Measurements, Recurring [Member]
Key economic assumptions and the sensitivity of the current fair value for single family MSRs
Fair value of single family MSR	136,897	87,396
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
Key economic assumptions and the sensitivity of the current fair value for single family MSRs
Fair value of single family MSR	$ 136,897	$ 87,396