Mortgage Servicing Rights Summary of Changes in Mortgage Servicing Rights (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Valuation allowance:
Estimated fair value of MSRs	$ 38,200,000	$ 45,300,000
Mortgage
Amortized cost:
Balance at beginning of year	40,944,000	42,148,000
Originations of mortgage servicing rights	5,485,000	6,166,000
Amortization expense	(7,607,000)	(7,370,000)
Balance at end of year	38,822,000	40,944,000
Valuation allowance:
Balance at beginning of year	0	0
Net additions to the valuation allowance	(1,291,000)	0
Balance at end of year	(1,291,000)	0
Net MSRs at end of year	37,531,000	$ 40,944,000
Amortization [Abstract]
2017	6,538,000
2018	6,087,000
2019	5,590,000
2020	5,043,000
2021	$ 4,443,000