Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs - TDR Rollforward (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Troubled Debt Restructuring Activity [Roll Forward]
Beginning balance	$ 26,329	$ 8,588
Additions		33,192	$ 5,122
Ending balance	8,478	26,329	8,588
Accruing
Troubled Debt Restructuring Activity [Roll Forward]
Beginning balance	1,796	2,291	2,743
Additions	0	15,819	0
Net payments	(50)	(1,923)	(120)
Returned to performing status	0	0	0
Net transfers from (to) non-accrual	120	(14,391)	(332)
Ending balance	1,866	1,796	2,291
Non-accrual
Troubled Debt Restructuring Activity [Roll Forward]
Beginning balance	24,533	6,297	2,324
Additions	527	14,570	6,205
Net payments	(14,403)	(4,380)	(1,072)
Charge-offs	(3,925)	(6,345)	(1,492)
Transfers to OREO	0	0	0
Loans sold	0	0	0
Net transfers (to) from accruing	(120)	14,391	332
Ending balance	$ 6,612	$ 24,533	$ 6,297