Loans and Asset Quality Information (Summary of Nonperforming Assets) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Oct. 01, 2017	Mar. 03, 2017
Loans and Leases Receivable Disclosure [Line Items]
Nonaccrual loans	$ 17,375	$ 22,575
Total loans	4,337,713	4,247,765	$ 4,149,459
Foreclosed properties	5,107	7,440	8,296
Purchased credit impaired loans not included above	14,175	17,393	20,832
Nonperforming assets
Loans and Leases Receivable Disclosure [Line Items]
Nonaccrual loans	17,375	22,575	25,494
TDRs- accruing	11,890	13,418	17,386
Accruing loans 90 days past due	0	0	0
Total loans	29,265	35,993	42,880
Foreclosed properties	5,107	7,440	8,296
Total nonperforming assets	34,372	43,433	51,176
Purchased Impaired Loans
Loans and Leases Receivable Disclosure [Line Items]
Recorded loans with a fair value				$ 9,900	$ 19,300
Carolina Bank Holdings, Inc. | Accruing 90 Days or More Past Due | Purchased Impaired Loans
Loans and Leases Receivable Disclosure [Line Items]
Recorded loans with a fair value	$ 600	$ 600	$ 500