Retirement Benefits (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2020 USD ($) person	Mar. 31, 2019 USD ($)
Postemployment Benefits [Abstract]
Service cost	$ 188	$ 174
Interest cost	270	303
Expected return on plan assets	(687)	(637)
Amortization of net loss	169	212
Net Periodic Benefit Expense	$ (60)	$ 52
Number of active, vested, terminated and retired persons in the Plan | person	348