Loans - Maturities and Rate Sensitivity (Details 3) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	$ 1,894,742	$ 1,799,155	$ 1,433,702
Fixed Rate	341,499
Floating Rate	1,553,243
Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	392,321
Fixed Rate	35,245
Floating Rate	357,076
Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	1,007,451
Fixed Rate	209,281
Floating Rate	798,170
Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	494,970
Fixed Rate	96,973
Floating Rate	397,997
Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	795,483	788,410	710,915
Commercial & Industrial [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	284,537
Commercial & Industrial [Member] | Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	472,312
Commercial & Industrial [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	38,634
Owner occupied commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	176,453	163,592	142,484
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	12,295
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	73,917
Owner occupied commercial real estate [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	90,241
Commerical real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	383,863	339,006	281,882
Commerical real estate [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	34,582
Commerical real estate [Member] | Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	247,132
Commerical real estate [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	102,149
Construction, land & land development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	290,469	240,666	188,691
Construction, land & land development [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	49,991
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	154,551
Construction, land & land development [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	85,927
Residential mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	234,026	257,066	104,913
Residential mortgage [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	4,672
Residential mortgage [Member] | Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	51,990
Residential mortgage [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	177,364
Consumer and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	14,448	$ 10,415	$ 4,817
Consumer and other [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	6,244
Consumer and other [Member] | Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	7,549
Consumer and other [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	$ 655