Fair Value Measurements, Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis (Details) - USD ($) $ in Thousands		6 Months Ended		12 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Mortgage servicing rights		$ 69,839		$ 81,012
Mortgage Servicing Rights (MSR) Impairment (Recovery)		(146)	$ 607
Equity Securities without Readily Determinable Fair Value, Amount		13,000		0
Equity Securities, FV-NI and without Readily Determinable Fair Value		15,066		1,568
Fair Value, Inputs, Level 3
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Equity Securities without Readily Determinable Fair Value, Amount		13,444		0
Equity Securities, FV-NI and without Readily Determinable Fair Value		13,444		0
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 2
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Other Real Estate Owned Fair Value Disclosure	[1]	519		2,200
Foreclosure / OREO expense, net		(1,115)		(1,545)
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3
Assets and Liabilities Measured at Fair Value on a Non-recurring Basis
Impaired loans	[2]	74,931		26,191
Provision for Credit Losses, Impaired Loans	[3]	(42,735)		(14,521)
Mortgage servicing rights		69,839		81,012
Mortgage Servicing Rights (MSR) Impairment (Recovery)		$ (146)		$ (545)

[1] (c) If the fair value of the collateral exceeds the carrying amount of the asset, no charge off or adjustment is necessary, the asset is not considered to be carried at fair value, and is therefore not included in the table.

[2]
(a) Represents individually evaluated impaired loans, net of the related allowance for loan losses.

[3] (b) Represents provision for credit losses on individually evaluated impaired loans.