Portfolio Loans - Summary of Recorded Investment by Risk Category of Portfolio Loans by Portfolio Class and Category (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, including unearned loan costs	$ 2,542,555	$ 2,433,916
Non-Covered Loans
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	2,541,527	2,433,021
Portfolio loans, including unearned loan costs	2,542,555	2,433,916
Non-Covered Loans | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	1,335,008	1,270,259
Non-Covered Loans | CRE - owner occupied
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	371,030	357,503
Non-Covered Loans | Commercial Real Estate Investor Owned
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	418,111	413,026
Non-Covered Loans | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	150,740	144,773
Non-Covered Loans | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	185,587	185,252
Non-Covered Loans | Consumer and other
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	81,051	62,208
Portfolio loans, including unearned loan costs	82,079	63,103
Pass (1-6) | Non-Covered Loans
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, including unearned loan costs	2,337,387	2,229,430
Pass (1-6) | Non-Covered Loans | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	1,223,114	1,167,751
Pass (1-6) | Non-Covered Loans | CRE - owner occupied
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	349,481	334,347
Pass (1-6) | Non-Covered Loans | Commercial Real Estate Investor Owned
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	383,373	372,818
Pass (1-6) | Non-Covered Loans | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	130,879	123,260
Pass (1-6) | Non-Covered Loans | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	168,995	168,543
Pass (1-6) | Non-Covered Loans | Consumer and other
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, including unearned loan costs	81,545	62,711
Watch (7) | Non-Covered Loans
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, including unearned loan costs	145,379	128,484
Watch (7) | Non-Covered Loans | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	81,660	62,315
Watch (7) | Non-Covered Loans | CRE - owner occupied
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	17,062	18,025
Watch (7) | Non-Covered Loans | Commercial Real Estate Investor Owned
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	23,703	24,088
Watch (7) | Non-Covered Loans | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	12,300	12,993
Watch (7) | Non-Covered Loans | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	10,610	11,012
Watch (7) | Non-Covered Loans | Consumer and other
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, including unearned loan costs	44	51
Substandard (8) | Non-Covered Loans
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, including unearned loan costs	59,087	76,002
Substandard (8) | Non-Covered Loans | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	30,234	40,193
Substandard (8) | Non-Covered Loans | CRE - owner occupied
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	4,487	5,131
Substandard (8) | Non-Covered Loans | Commercial Real Estate Investor Owned
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	11,035	16,120
Substandard (8) | Non-Covered Loans | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	6,859	8,520
Substandard (8) | Non-Covered Loans | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	5,982	5,697
Substandard (8) | Non-Covered Loans | Consumer and other
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, including unearned loan costs	490	341
Doubtful (9) | Non-Covered Loans
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, including unearned loan costs	702	0
Doubtful (9) | Non-Covered Loans | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	0	0
Doubtful (9) | Non-Covered Loans | CRE - owner occupied
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	0	0
Doubtful (9) | Non-Covered Loans | Commercial Real Estate Investor Owned
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	0	0
Doubtful (9) | Non-Covered Loans | Construction and land development
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	702	0
Doubtful (9) | Non-Covered Loans | Residential real estate
Financing Receivable, Recorded Investment [Line Items]
Portfolio Loans	0	0
Doubtful (9) | Non-Covered Loans | Consumer and other
Financing Receivable, Recorded Investment [Line Items]
Portfolio loans, including unearned loan costs	$ 0	$ 0