Pension and Other Postretirement Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Compensation And Retirement Disclosure [Abstract]
Term of insurance contracts to fund benefits	5 years
Curtailment	$ 2,621	$ 1,219
Assumptions used calculating benefit obligation, discount rate	1.05%	1.75%