Past Due Loans, Allowance For Credit Losses, Impaired Loans, and TDRs (Details) - TDR Rollforward - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Troubled Debt Restructuring Activity [Roll Forward]
Beginning balance	$ 5,067	$ 23,608
Additions	5,122	445	$ 24,619
Ending balance	8,588	5,067	23,608
Accruing
Troubled Debt Restructuring Activity [Roll Forward]
Beginning balance	2,743	3,704	23,770
Additions	0	120	804
Net (payments) advances	(120)	(774)	(1,440)
Returned to performing status	0	0	(20,656)
Net transfers (to) from non-accrual	(332)	(307)	1,226
Ending balance	2,291	2,743	3,704
Non-accrual
Troubled Debt Restructuring Activity [Roll Forward]
Beginning balance	2,324	19,904	4,083
Additions	6,205	325	23,815
Net (payments) advances	(1,072)	(15,525)	1,991
Charge-offs	(1,492)	(2,687)	(8,457)
Transfers to OREO	0	0	(302)
Loans sold	0	0	0
Net transfers from (to) accruing	332	307	(1,226)
Ending balance	$ 6,297	$ 2,324	$ 19,904