Loans - Maturities and Rate Sensitivity (Details 3) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	$ 1,810,842	$ 1,799,155	$ 1,404,275
Fixed Rate	366,278
Floating Rate	1,444,564
Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	369,753
Fixed Rate	44,040
Floating Rate	325,713
Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	956,572
Fixed Rate	223,689
Floating Rate	732,883
Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	484,517
Fixed Rate	98,549
Floating Rate	385,968
Commercial & Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	744,380	788,410	675,812
Commercial & Industrial [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	243,532
Commercial & Industrial [Member] | Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	444,662
Commercial & Industrial [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	56,186
Owner occupied commercial real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	166,604	163,592	152,515
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	24,158
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	61,166
Owner occupied commercial real estate [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	81,280
Commerical real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	367,071	339,006	310,379
Commerical real estate [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	25,263
Commerical real estate [Member] | Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	265,775
Commerical real estate [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	76,033
Construction, land & land development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	273,125	240,666	152,327
Construction, land & land development [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	65,566
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	123,082
Construction, land & land development [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	84,477
Residential mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	249,591	257,066	107,408
Residential mortgage [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	4,905
Residential mortgage [Member] | Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	58,945
Residential mortgage [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	185,741
Consumer and other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	10,071	10,415	5,834
Consumer and other [Member] | Due in One Year or Less
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	6,329
Consumer and other [Member] | Due After One Year Through Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	2,942
Consumer and other [Member] | Due After Five Years
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans held for investment	$ 800