Fair Value Measurements - Schedule of Estimated Fair Values of Financial Instruments Not Recorded at Fair Value on Balance Sheet (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Estimated fair value | Securities held to maturity
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial assets not on condensed consolidated balance sheets at fair value	$ 77,831	$ 79,639
Estimated fair value | Portfolio loans, net
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial assets not on condensed consolidated balance sheets at fair value	3,867,481	3,125,701
Estimated fair value | State tax credits, held for sale
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial assets not on condensed consolidated balance sheets at fair value	35,583	37,679
Estimated fair value | Deposits
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	3,919,379	3,232,414
Estimated fair value | Subordinated debentures and notes
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	99,873	86,052
Estimated fair value | Federal Home Loan Bank advances
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	201,397
Estimated fair value | Other Borrowings
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	217,077	276,905
Level 1 | Securities held to maturity
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial assets not on condensed consolidated balance sheets at fair value	0	0
Level 1 | Portfolio loans, net
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial assets not on condensed consolidated balance sheets at fair value	0	0
Level 1 | State tax credits, held for sale
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial assets not on condensed consolidated balance sheets at fair value	0	0
Level 1 | Deposits
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	3,328,169	2,760,202
Level 1 | Subordinated debentures and notes
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	0	0
Level 1 | Federal Home Loan Bank advances
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	0
Level 1 | Other Borrowings
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	0	0
Level 2 | Securities held to maturity
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial assets not on condensed consolidated balance sheets at fair value	77,831	79,639
Level 2 | Portfolio loans, net
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial assets not on condensed consolidated balance sheets at fair value	0	0
Level 2 | State tax credits, held for sale
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial assets not on condensed consolidated balance sheets at fair value	0	0
Level 2 | Deposits
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	0	0
Level 2 | Subordinated debentures and notes
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	99,873	86,052
Level 2 | Federal Home Loan Bank advances
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	201,397
Level 2 | Other Borrowings
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	217,077	276,905
Level 3 | Securities held to maturity
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial assets not on condensed consolidated balance sheets at fair value	0	0
Level 3 | Portfolio loans, net
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial assets not on condensed consolidated balance sheets at fair value	3,867,481	3,125,701
Level 3 | State tax credits, held for sale
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial assets not on condensed consolidated balance sheets at fair value	35,583	37,679
Level 3 | Deposits
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	591,210	472,212
Level 3 | Subordinated debentures and notes
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	0	0
Level 3 | Federal Home Loan Bank advances
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	0
Level 3 | Other Borrowings
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Financial liabilities not on condensed consolidated balance sheets at fair value	$ 0	$ 0