Loans - Portfolio by Type and Class (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 3,189,436	$ 3,130,669	$ 1,894,742
Loans held for sale	6,253	384
Originated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	2,215,064	1,933,557
Loans held for sale	6,253	384
Acquired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	974,372	1,197,112
Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,128,541	1,206,452	795,483
Commercial & Industrial [Member] | Originated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	905,683	850,048
Commercial & Industrial [Member] | Acquired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	222,858	356,404
Owner occupied commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	366,587	353,889	176,453
Owner occupied commercial real estate [Member] | Originated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	222,762	188,908
Owner occupied commercial real estate [Member] | Acquired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	143,825	164,981
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	1,078,434	904,115	383,863
Commercial real estate [Member] | Originated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	710,431	521,887
Commercial real estate [Member] | Acquired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	368,003	382,228
Construction, land & land development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	334,925	358,813	290,469
Construction, land & land development [Member] | Originated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	240,098	242,611
Construction, land & land development [Member] | Acquired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	94,827	116,202
Residential mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	270,337	293,483	234,026
Residential mortgage [Member] | Originated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	128,168	120,260
Residential mortgage [Member] | Acquired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	142,169	173,223
Consumer and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	10,612	13,917	$ 14,448
Consumer and other [Member] | Originated [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	7,922	9,843
Consumer and other [Member] | Acquired [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans held for investment	$ 2,690	$ 4,074