Retirement Plans (Details) - Defined Benefit Plan [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 400	$ 358	$ 1,196	$ 1,076
Interest cost	256	315	763	954
Expected return on plan assets	(209)	(224)	(622)	(684)
Recognized actuarial loss (gain)	16	(40)	47	(118)
Total defined benefit expense	$ 463	$ 409	$ 1,384	$ 1,228