Loans - Portfolio by Type and Class (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 3,012,275	$ 3,098,220	$ 3,168,183
Loans held for sale	17,350	23,989
Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,282,211	2,301,928	2,075,548
Loans held for sale	17,350	23,989
Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	730,064	796,292	1,092,635
Commercial & Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,012,982	1,053,925
Commercial & Industrial | Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	889,848	904,331	847,538
Commercial & Industrial | Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	123,134	149,594	283,172
Owner occupied commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	415,595	394,210
Owner occupied commercial real estate | Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	292,413	264,876	205,050
Owner occupied commercial real estate | Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	123,182	129,334	162,457
Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,129,031	1,143,751
Commercial real estate | Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	809,026	816,029	636,539
Commercial real estate | Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	320,005	327,722	383,860
Construction, land & land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	201,946	249,704
Construction, land & land development | Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	151,114	179,999	252,642
Construction, land & land development | Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	50,832	69,705	103,565
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	241,839	245,191
Residential mortgage | Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	130,799	127,445	123,941
Residential mortgage | Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	111,040	117,746	156,295
Consumer and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	10,882	11,439
Consumer and other | Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	9,011	9,248	9,838
Consumer and other | Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 1,871	$ 2,191	$ 3,286