Loans and Asset Quality Information (Summary of Nonperforming Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Oct. 01, 2017	Mar. 03, 2017
Loans and Leases Receivable Disclosure [Line Items]
Nonaccrual loans	$ 31,656	$ 24,866
Total loans	4,813,736	4,453,466	$ 4,396,544
Foreclosed properties	2,741	3,873
Purchased credit impaired loans not included above	9,616	12,664
Purchased Impaired Loans
Loans and Leases Receivable Disclosure [Line Items]
Recorded loans with a fair value				$ 9,900	$ 19,300
Purchased Impaired Loans | Carolina Bank Holdings, Inc. | Accruing 90 Days or More Past Due
Loans and Leases Receivable Disclosure [Line Items]
Recorded loans with a fair value	800	800
Nonperforming assets
Loans and Leases Receivable Disclosure [Line Items]
Nonaccrual loans	31,656	24,866
TDR's - accruing	9,896	9,053
Accruing loans > 90 days past due	0	0
Total loans	41,552	33,919
Foreclosed properties	2,741	3,873
Total nonperforming assets	$ 44,293	$ 37,792