Fair Value Measurements - Summary of Carrying Amount and Fair Values of Financial Instruments Reported on the Balance Sheets (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Balance sheet assets
Securities available for sale	$ 593,685	$ 460,797
Securities held to maturity	79,236	80,463
State tax credits held for sale	1,458	3,585
Carrying Amount
Balance sheet assets
Cash and due from banks	73,387	54,288
Federal funds sold	1,112	446
Interest-bearing deposits	137,197	145,048
Securities available for sale	593,685	460,797
Securities held to maturity	79,236	80,463
Other investments, at cost	24,222	14,840
Loans held for sale	5,380	9,562
Derivative financial instruments	5,403	4,016
Portfolio loans, net	3,846,439	3,114,752
State tax credits held for sale	35,431	38,071
Accrued interest receivable	12,229	11,117
Balance sheet liabilities
Deposits	4,031,620	3,233,361
Subordinated debentures	118,067	105,540
Federal Home Loan Bank advances	151,115	0
Other borrowings	235,052	276,980
Derivative financial instruments	5,403	4,016
Accrued interest payable	1,914	1,105
Estimated fair value
Balance sheet assets
Cash and due from banks	73,387	54,288
Federal funds sold	1,112	446
Interest-bearing deposits	137,197	145,048
Securities available for sale	593,685	460,797
Securities held to maturity	78,617	79,639
Other investments, at cost	24,222	14,840
Loans held for sale	5,380	9,562
Derivative financial instruments	5,403	4,016
Portfolio loans, net	3,852,858	3,125,701
State tax credits held for sale	37,041	41,264
Accrued interest receivable	12,229	11,117
Balance sheet liabilities
Deposits	4,029,423	3,232,414
Subordinated debentures	99,517	86,052
Federal Home Loan Bank advances	151,020	0
Other borrowings	234,964	276,905
Derivative financial instruments	5,403	4,016
Accrued interest payable	$ 1,914	$ 1,105