Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs - TDR Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Troubled Debt Restructuring Activity [Roll Forward]
Beginning balance	$ 8,478	$ 26,329
Additions	15,804		$ 33,192
Ending balance	21,747	8,478	26,329
Accruing
Troubled Debt Restructuring Activity [Roll Forward]
Beginning balance	1,866	1,796	2,291
Additions	12	0	15,819
Net payments	(262)	(50)	(1,923)
Returned to performing status	0	0	0
Net transfers (to) from non-accrual	(383)	120	(14,391)
Ending balance	1,233	1,866	1,796
Non-accrual
Troubled Debt Restructuring Activity [Roll Forward]
Beginning balance	6,612	24,533	6,297
Additions	18,089	527	14,570
Net payments	(1,013)	(14,403)	(4,380)
Charge-offs	(3,557)	(3,925)	(6,345)
Transfers to OREO	0	0	0
Loans sold	0	0	0
Net transfers from (to) accruing	383	(120)	14,391
Ending balance	$ 20,514	$ 6,612	$ 24,533