Retirement Plans - Schedule of Accumulated Benefit Obligations in Excess of Fair Value of Plan Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
United States [Member]
Projected benefit obligation, end of year	$ 59,600	$ 63,700
Accumulated benefit obligation, end of year	59,600	63,700
Plan assets at fair value, end of year	43,100	48,800
Foreign Plan [Member]
Projected benefit obligation, end of year	24,600	26,800
Accumulated benefit obligation, end of year	24,600	26,800
Plan assets at fair value, end of year	$ 16,000	$ 17,500