Income Taxes - (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Deferred tax assets
Allowance for loan losses	$ 20,541	$ 17,430	$ 17,244
Loans	31,477	26,239	14,132
Deferred compensation	11,628	17,060	8,146
Securities	2,346	2,572	1,360
Net unrealized losses on securities - OCI	5,093	6,065	5,404
Impairment of assets	3,129	3,271	3,765
Federal and State net operating loss carryforwards	3,808	3,681	1,423
Other	8,027	4,927	2,039
Gross deferred tax assets	86,049	81,245	53,513
Valuation allowance on state net operating loss carryforwards	0	0	0
Total deferred tax assets	86,049	81,245	53,513
Deferred tax liabilities
FDIC loss-share indemnification asset	1,579	1,927	2,867
Investment in partnerships	2,163	2,507	2,608
Core deposit intangible	3,015	3,386	1,661
Fixed assets	1,668	673	3,116
Mortgage servicing rights	3,976	4,032	0
Subordinated debt	4,181	4,287	4,402
Other	4,714	2,364	566
Total deferred tax liabilities	21,296	19,176	15,220
Net deferred tax assets	$ 64,753	$ 62,069	$ 38,293