Portfolio Loans - Summary of Non-covered Loans by Category (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio loans, including unearned loan costs	$ 2,294,905	$ 2,137,313
Non-Covered Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	2,294,905	2,137,313
Portfolio Loans, net of unearned loan costs	2,293,828	2,136,292
Unearned loan costs, net	1,077	1,021
Portfolio loans, including unearned loan costs	2,294,905	2,137,313
Non-Covered Loans | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	123,888	117,032
Non-Covered Loans | Commercial real estate - Investor owned
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	391,791	437,688
Non-Covered Loans | Commercial real estate - Owner occupied
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	366,724	341,631
Non-Covered Loans | Residential real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	187,594	158,527
Non-Covered Loans | Real Estate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	1,069,997	1,054,878
Non-Covered Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	1,172,015	1,041,576
Non-Covered Loans | Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Portfolio Loans	52,893	40,859
Portfolio Loans, net of unearned loan costs	$ 51,816	$ 39,838