Mortgage Servicing Rights Summary of Changes in Mortgage Servicing Rights (Details) - Residential Mortgage [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Amortized Cost:
Balance at beginning of period	$ 37,748	$ 38,543	$ 37,663	$ 38,822
Originations of mortgage servicing rights	1,746	1,203	3,229	2,386
Amortization	(1,600)	(1,566)	(2,998)	(3,028)
Balance at end of period	37,894	38,180	37,894	38,180
Valuation allowance:
Balance at beginning of period	0	(1,291)	0	(1,291)
Balance at end of period	0	0	0	0
Net MSRs at end of period	$ 37,894	$ 38,180	$ 37,894	$ 38,180