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, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Amortized Cost:
Balance at beginning of period	$ 38,180	$ 39,874	$ 38,822	$ 40,944
Originations of mortgage servicing rights	1,333	1,499	3,719	3,927
Amortization	(1,639)	(2,064)	(4,667)	(5,562)
Balance at end of period	37,874	39,309	37,874	39,309
Valuation allowance:
Balance at beginning of period	0	(1,721)	(1,291)	0
(Additions) reductions to valuation allowance	0	1,280	(1,291)	3,001
Balance at end of period	0	(3,001)	0	(3,001)
Net MSRs at end of period	$ 37,874	$ 36,308	$ 37,874	$ 36,308