Loans and Asset Quality Information (Summary of Nonperforming Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Oct. 01, 2017	Mar. 03, 2017
Loans and Leases Receivable Disclosure [Line Items]
Nonaccrual loans	$ 25,066	$ 24,866
Total loans	4,552,708	4,453,466	$ 4,303,787
Foreclosed properties	3,487	3,873
Purchased credit impaired loans not included above	9,839	12,664
Nonperforming assets
Loans and Leases Receivable Disclosure [Line Items]
Nonaccrual loans	25,066	24,866
Restructured loans - accruing	9,747	9,053
Accruing loans 90 days past due	0	0
Total loans	34,813	33,919
Foreclosed properties	3,487	3,873
Total nonperforming assets	38,300	37,792
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	$ 700	$ 800