Fair Value Measurements - Summary of Carrying Amount and Fair Values of Financial Instruments Reported on the Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Balance sheet assets
Securities available for sale	$ 478,514	$ 451,770
Securities held to maturity	42,514	43,714
State tax credits held for sale	4,774	5,941
Carrying Amount
Balance sheet assets
Cash and due from banks	50,370	47,935
Federal funds sold	317	91
Interest-bearing deposits	60,609	47,131
Securities available for sale	478,514	451,770
Securities held to maturity	42,514	43,714
Other investments, at cost	17,403	17,455
Loans held for sale	9,669	6,598
Derivative financial instruments	2,264	1,155
Portfolio loans, net	2,896,389	2,781,879
State tax credits held for sale	44,918	45,850
Accrued interest receivable	8,123	8,399
Balance sheet liabilities
Deposits	3,028,236	2,784,591
Subordinated debentures	56,807	56,807
Federal Home Loan Bank advances	78,000	110,000
Other borrowings	200,362	270,326
Derivative financial instruments	2,264	1,155
Accrued interest payable	625	629
Estimated fair value
Balance sheet assets
Cash and due from banks	50,370	47,935
Federal funds sold	317	91
Interest-bearing deposits	60,609	47,131
Securities available for sale	478,514	451,770
Securities held to maturity	43,837	43,441
Other investments, at cost	17,403	17,455
Loans held for sale	9,669	6,598
Derivative financial instruments	2,264	1,155
Portfolio loans, net	2,902,083	2,782,704
State tax credits held for sale	49,961	49,588
Accrued interest receivable	8,123	8,399
Balance sheet liabilities
Deposits	3,030,334	2,784,654
Subordinated debentures	35,771	35,432
Federal Home Loan Bank advances	78,000	109,994
Other borrowings	200,332	270,286
Derivative financial instruments	2,264	1,155
Accrued interest payable	$ 625	$ 629