Fair Value Measurements, Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Mortgage servicing rights	$ 59,414		$ 61,341
Mortgage Servicing Rights (MSR) Impairment (Recovery)	(909)	$ (243)
Fair Value, Inputs, Level 2 [Member]
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Loans held for sale	129,398		124,915
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 2 [Member]
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Loans held for sale	129,398		124,915
market valuation adjustment, loans held for sale	0		(155)
Fair Value, Measurements, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member]
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Impaired loans	84,664		41,891
Provision for Credit Losses, Impaired Loans	(15,097)		(7,796)
Mortgage servicing rights	61,410		70,686
Mortgage Servicing Rights (MSR) Impairment (Recovery)	$ 909		$ (425)