Retirement Plans (Details) - Defined Benefit Plan [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 359	$ 366	$ 718	$ 734
Interest cost	319	286	639	575
Expected return on plan assets	(229)	(241)	(460)	(486)
Recognized actuarial gain	(39)	(27)	(78)	(54)
Total defined benefit expense	$ 410	$ 384	$ 819	$ 769