Retirement Plans (Details) - Defined Benefit Plan [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 359	$ 368
Interest cost	320	289
Expected return on plan assets	(231)	(245)
Recognized actuarial gain	(39)	(27)
Total defined benefit expense	$ 409	$ 385