Mortgage Servicing Rights - Significant Economic Assumptions (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Fixed
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Weighted-average OAS	4.88%	4.62%
Weighted-average life, in years	3 years 4 months 17 days	4 years 5 months 15 days
Adjustable
Assumption for Fair Value as of Balance Sheet Date of Assets or Liabilities that relate to Transferor's Continuing Involvement [Line Items]
Weighted-average OAS	7.85%	7.61%
Weighted-average life, in years	3 years 18 days	3 years 5 months 4 days