Fair Value Measurements (Details 3) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Impaired loans measured at fair value on a nonrecurring basis
Impaired loans	$ 9,251	$ 4,101
OREO	7,392	6,741
Mortgage servicing rights		26,302
Total	16,643	37,144
Quoted Prices In Active Markets for Identical Assets (Level 1)
Impaired loans measured at fair value on a nonrecurring basis
Impaired loans	0	0
OREO	0	0
Mortgage servicing rights		0
Total	0	0
Significant Other Observable Inputs (Level 2)
Impaired loans measured at fair value on a nonrecurring basis
Impaired loans	0	0
OREO	0	0
Mortgage servicing rights		0
Total	0	0
Significant Unobservable Inputs (Level 3)
Impaired loans measured at fair value on a nonrecurring basis
Impaired loans	9,251	4,101
OREO	7,392	6,741
Mortgage servicing rights		26,302
Total	$ 16,643	$ 37,144