Loans - Portfolio by Type and Class (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 3,123,355	$ 3,098,220	$ 3,189,436
Loans held for sale	18,030	23,989
Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,476,754	2,301,928	2,215,064
Loans held for sale	16,330	23,989
Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	646,601	796,292	974,372
Loans held for sale	1,700
Commercial & Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,144,332	1,053,925
Commercial & Industrial | Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,052,354	904,331	905,683
Commercial & Industrial | Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	91,978	149,594	222,858
Owner occupied commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	407,317	394,210
Owner occupied commercial real estate | Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	306,514	264,876	222,762
Owner occupied commercial real estate | Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	100,803	129,334	143,825
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,109,237	1,143,751
Commercial real estate | Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	807,341	816,029	710,431
Commercial real estate | Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	301,896	327,722	368,003
Construction, land & land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	201,992	249,704
Construction, land & land development | Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	153,522	179,999	240,098
Construction, land & land development | Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	48,470	69,705	94,827
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	239,834	245,191
Residential mortgage | Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	137,918	127,445	128,168
Residential mortgage | Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	101,916	117,746	142,169
Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	20,643	11,439
Consumer and other | Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	19,105	9,248	7,922
Consumer and other | Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 1,538	$ 2,191	$ 2,690