Loans - Maturities and Rate Sensitivity (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	$ 3,189,436	$ 3,130,669	$ 1,894,742
Fixed Rate	689,806
Floating Rate	2,499,630
Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	655,113
Fixed Rate	75,299
Floating Rate	579,814
Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	1,850,333
Fixed Rate	490,934
Floating Rate	1,359,399
Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	683,990
Fixed Rate	123,573
Floating Rate	560,417
Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	1,128,541	1,206,452	795,483
Commercial & Industrial [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	432,407
Commercial & Industrial [Member] | Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	644,544
Commercial & Industrial [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	51,590
Owner occupied commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	366,587	353,889	176,453
Owner occupied commercial real estate [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	26,978
Owner occupied commercial real estate [Member] | Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	183,944
Owner occupied commercial real estate [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	155,665
Commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	1,078,434	904,115	383,863
Commercial real estate [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	61,751
Commercial real estate [Member] | Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	800,924
Commercial real estate [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	215,759
Construction, land & land development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	334,925	358,813	290,469
Construction, land & land development [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	108,289
Construction, land & land development [Member] | Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	149,176
Construction, land & land development [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	77,460
Residential mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	270,337	293,483	234,026
Residential mortgage [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	18,884
Residential mortgage [Member] | Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	68,852
Residential mortgage [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	182,601
Consumer and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	10,612	$ 13,917	$ 14,448
Consumer and other [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	6,804
Consumer and other [Member] | Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	2,893
Consumer and other [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	$ 915