Income Taxes - (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Deferred tax assets
Allowance for loan losses	$ 20,566	$ 19,934	$ 20,541
Loans	19,575	23,240	31,477
Deferred compensation	9,845	11,254	11,628
Securities	2,440	2,439	2,346
Net unrealized losses on securities - OCI	6,670	10,096	5,093
Impairment of assets	1,986	2,512	3,129
Federal and State net operating loss carryforwards	3,081	2,867	3,808
Intangibles	1,758	1,247	0
Other	3,577	3,463	8,027
Total deferred tax assets	69,498	77,052	86,049
Deferred tax liabilities
FDIC loss-share indemnification asset	0	0	1,579
Investment in partnerships	1,272	1,556	2,163
Core deposit intangible	0	0	3,015
Fixed assets	1,875	2,517	1,668
Mortgage servicing rights	3,360	3,360	3,976
Junior subordinated debt	4,004	4,111	4,181
Other	2,000	2,876	4,714
Total deferred tax liabilities	12,511	14,420	21,296
Net deferred tax assets	$ 56,987	$ 62,632	$ 64,753