Mortgage Servicing Rights Summary of Changes in Mortgage Servicing Rights (Details) - Residential Mortgage [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Amortized Cost:
Balance at beginning of period	$ 37,894	$ 38,180	$ 37,663	$ 38,822
Originations of mortgage servicing rights	2,018	1,333	5,247	3,719
Amortization	(1,684)	(1,639)	(4,682)	(4,667)
Balance at end of period	38,228	37,874	38,228	37,874
Valuation allowance:
Balance at beginning of period	0	0	0	(1,291)
Balance at end of period	0	0	0	0
Net MSRs at end of period	$ 38,228	$ 37,874	$ 38,228	$ 37,874