Fair Value Measurements - Summary of Carrying Amount and Fair Values of Financial Instruments Reported on the Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Balance sheet assets
Securities available for sale	$ 451,770	$ 400,146
Securities held to maturity	43,714	45,985
State tax credits held for sale	5,941	11,689
Carrying Amount
Balance sheet assets
Cash and due from banks	47,935	42,903
Federal funds sold	91	35
Interest-bearing deposits	47,131	63,058
Securities available for sale	451,770	400,146
Securities held to maturity	43,714	45,985
Other investments, at cost	17,455	17,037
Loans held for sale	6,598	4,033
Derivative financial instruments	1,155	909
Portfolio loans, net	2,781,879	2,487,424
State tax credits held for sale	45,850	38,309
Accrued interest receivable	8,399	7,956
Balance sheet liabilities
Deposits	2,784,591	2,491,510
Subordinated debentures	56,807	56,807
Federal Home Loan Bank advances	110,000	144,000
Other borrowings	270,326	239,883
Derivative financial instruments	1,155	907
Accrued interest payable	629	843
Estimated fair value
Balance sheet assets
Cash and due from banks	47,935	42,903
Federal funds sold	91	35
Interest-bearing deposits	47,131	63,058
Securities available for sale	451,770	400,146
Securities held to maturity	43,441	45,795
Other investments, at cost	17,455	17,037
Loans held for sale	6,598	4,033
Derivative financial instruments	1,155	909
Portfolio loans, net	2,782,704	2,482,700
State tax credits held for sale	49,588	42,970
Accrued interest receivable	8,399	7,956
Balance sheet liabilities
Deposits	2,784,654	2,494,624
Subordinated debentures	35,432	34,124
Federal Home Loan Bank advances	109,994	144,000
Other borrowings	270,286	239,950
Derivative financial instruments	1,155	907
Accrued interest payable	$ 629	$ 843