Income Taxes - Significant Components of The Company's Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Deferred tax assets
Allowance for loan losses	$ 14,025	$ 13,966
Loans	13,697	15,062
Deferred compensation	6,871	7,093
Securities	6,044	3,659
Net unrealized losses on securities - OCI	0	0
Impairment of assets	1,701	1,748
Federal and State net operating loss carryforwards	1,401	2,419
Intangibles	0	0
Other	5,204	4,722
Total deferred tax assets	48,943	48,669
Deferred tax liabilities
Investment in partnerships	655	757
Fixed assets	3,077	3,163
Mortgage servicing rights	10,440	10,139
Junior subordinated debt	2,363	2,394
Other	1,656	1,859
Total deferred tax liabilities	18,191	18,312
Net deferred tax assets	$ 30,752	$ 30,357