Fair Value Disclosures, Reconciliation for all Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) (Details) - Capitalized Mortgage Loan Servicing Rights [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Reconciliation for all assets and (liabilities) measured at fair value on a recurring basis using significant unobservable inputs (Level 3) [Roll Forward]
Beginning balance	$ 21,400	$ 15,699
Total gains (losses) realized and unrealized [Abstract]
Included in results of operations	(2,691)	1,029
Included in other comprehensive income (loss)	0	0
Purchases, issuances, settlements, maturities and calls	1,200	1,055
Transfers in and/or out of Level 3	0	0
Ending balance	19,909	17,783
Amount of total gains (losses) for the period included in earnings attributable to the change in unrealized gains (losses) relating to assets and liabilities still held at March 31	$ (2,691)	$ 1,029