Mortgage Servicing Rights (Economic Assumptions) (Details) - $ / loans	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Servicing Asset Key Economic Assumptions [Line Items]
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Prepayment Speed	13.32%	11.01%
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Cost to Service Loans	62.75	56.61
Conventional fixed loans
Servicing Asset Key Economic Assumptions [Line Items]
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Discount Rate	8.77%	9.31%
All loans excluding conventional fixed loans
Servicing Asset Key Economic Assumptions [Line Items]
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Discount Rate	9.77%	10.31%