Loans - Risk Category, Class of Loans and Recorded Investment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 3,817,377	$ 2,879,536
Construction & Land Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	343,125	160,116
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,639,992	1,357,593
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,038,810	836,787
Commercial and Financial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	606,014	370,589
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	189,436	154,452
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,722,027	2,803,241
Pass [Member] | Construction & Land Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	328,127	148,607
Pass [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,586,932	1,324,685
Pass [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,023,925	811,934
Pass [Member] | Commercial and Financial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	593,689	364,241
Pass [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	189,354	153,774
Special mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	47,545	28,017
Special mention [Member] | Construction & Land Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	10,414	5,037
Special mention [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	29,273	17,184
Special mention [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	4,621	1,780
Special mention [Member] | Commercial and Financial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,237	3,949
Special mention [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	0	67
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	47,494	48,279
Substandard [Member] | Construction & Land Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	4,584	6,472
Substandard [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	23,787	15,724
Substandard [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	10,203	23,073
Substandard [Member] | Commercial and Financial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	8,838	2,399
Substandard [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	82	611
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	311	0
Doubtful [Member] | Construction & Land Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Doubtful [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Doubtful [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	61	0
Doubtful [Member] | Commercial and Financial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	250	0
Doubtful [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 0	$ 0