Loans - Roll Forward of Activity In Allowance for Loan Losses (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018
Allowance for loan losses:
Beginning balance	$ 17,430	$ 26,888
Charge-offs	(1,942)	(1,836)
Recoveries	282	319
Provision	12,359	0
Ending balance	17,430	26,888	$ 28,129	$ 17,430	$ 25,371
Ending balance: individually evaluated for impairment			10,754		6,164
Ending balance: collectively evaluated for impairment			17,375		19,207
Loans:
Ending balance			880,037	899,785	1,137,255
Ending balance: individually evaluated for impairment			21,165		83,427
Ending balance: collectively evaluated for impairment			858,872		1,053,828
Commercial, financial and agricultural
Allowance for loan losses:
Beginning balance	10,633	20,577
Charge-offs	(1,775)	(1,524)
Recoveries	184	276
Provision	11,654	(264)
Ending balance	10,633	20,577	20,696	10,633	19,065
Ending balance: individually evaluated for impairment			10,680		5,968
Ending balance: collectively evaluated for impairment			10,016		13,097
Loans:
Ending balance			226,871	267,340	401,048
Ending balance: individually evaluated for impairment			15,934		55,092
Ending balance: collectively evaluated for impairment			210,937		345,956
Real estate – construction
Allowance for loan losses:
Beginning balance	140	596
Charge-offs	0	(2)
Recoveries	0	0
Provision	402	159
Ending balance	140	596	542	140	753
Ending balance: individually evaluated for impairment			0		94
Ending balance: collectively evaluated for impairment			542		659
Loans:
Ending balance			77,482	87,506	94,679
Ending balance: individually evaluated for impairment			424		192
Ending balance: collectively evaluated for impairment			77,058		94,487
Real estate – commercial
Allowance for loan losses:
Beginning balance	4,913	3,918
Charge-offs	0	(86)
Recoveries	30	6
Provision	557	(105)
Ending balance	4,913	3,918	5,500	4,913	3,733
Ending balance: individually evaluated for impairment			74		76
Ending balance: collectively evaluated for impairment			5,426		3,657
Loans:
Ending balance			409,694	368,449	444,277
Ending balance: individually evaluated for impairment			4,807		26,005
Ending balance: collectively evaluated for impairment			404,887		418,272
Real estate – residential
Allowance for loan losses:
Beginning balance	1,156	837
Charge-offs	0	(3)
Recoveries	1	1
Provision	(215)	64
Ending balance	1,156	837	942	1,156	899
Ending balance: individually evaluated for impairment			0		20
Ending balance: collectively evaluated for impairment			942		879
Loans:
Ending balance			126,043	132,435	145,671
Ending balance: individually evaluated for impairment			0		2,088
Ending balance: collectively evaluated for impairment			126,043		143,583
Consumer and other
Allowance for loan losses:
Beginning balance	585	957
Charge-offs	(167)	(221)
Recoveries	67	36
Provision	(36)	146
Ending balance	585	957	449	585	918
Ending balance: individually evaluated for impairment			0		6
Ending balance: collectively evaluated for impairment			449		912
Loans:
Ending balance			39,476	43,506	50,888
Ending balance: individually evaluated for impairment			0		50
Ending balance: collectively evaluated for impairment			39,476		50,838
Lease financing receivable
Allowance for loan losses:
Beginning balance	3	3
Charge-offs	0	0
Recoveries	0	0
Provision	(3)	0
Ending balance	$ 3	$ 3	0	3	3
Ending balance: individually evaluated for impairment			0		0
Ending balance: collectively evaluated for impairment			0		3
Loans:
Ending balance			471	$ 549	692
Ending balance: individually evaluated for impairment			0		0
Ending balance: collectively evaluated for impairment			$ 471		$ 692