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, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of year	$ (87)	$ 166
Unrecognized prior service cost	0	0
Amortization of loss, net	0	(9)	$ (9)
Actuarial gain	(46)	(70)	1
Balance at end of year	$ (41)	$ (87)	$ 166