Accumulated Other Comprehensive Income Reclassification Out Of Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net realized gain (loss) on investment		$ 1,340	$ (110)	$ 1,041
Prior year service cost		0	0
Unrecognized loss		0	0	(9)
Income before Income Taxes		39,823	27,069	30,271
Tax		(8,365)	(5,210)	(4,570)
Net income		31,458	21,859	25,701
Reclassification Out Of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net income		0	(93)	784
Reclassification Out Of Accumulated Other Comprehensive Income | Unrealized Gains And Losses On Available-For-Sale Securities
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net realized gain (loss) on investment		0	(117)	1,227
Other-than-temporary impairments		0	0	(26)
Income before Income Taxes		0	(117)	1,201
Tax		0	24	(411)
Net income		0	(93)	790
Reclassification Out Of Accumulated Other Comprehensive Income | Postretirement Benefits Plans
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Prior year service cost		0	0	0
Unrecognized loss		0	0	(9)
Income before Income Taxes	[1]	0	0	(9)
Tax		0	0	3
Net income		$ 0	$ 0	$ (6)

[1] These accumulated other comprehensive income components are not reclassified to net income in their entirety in the same reporting period. The amounts are presented within personnel expenses on the Consolidated Statements of Income as amortized. Amortization related to postretirement benefit plans is included in the computation of net periodic pension costs, as discussed in Note 10.