Retirement Agreements and Other Postretirement Benefit Plan Changes in Amounts Related to Accumulated Other Comprehensive Income, Pre-tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of year	$ 41	$ 87
Unrecognized prior service cost	0	0
Amortization of loss, net	0	0	$ (9)
Actuarial loss (gain)	41	(46)
Balance at end of year	$ 82	$ 41	$ 87