Income Taxes, Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current income tax expense (benefit) [Abstract]
Federal	$ 9,660	$ 12,994	$ (9,071)	[1]
State	3,000	2,622	205
Foreign	24,418	22,680	23,187
Current income tax expense, total	37,078	38,296	14,321
Deferred expense (benefit) [Abstract]
Federal	(6,918)	(17,246)	3,977
State	(565)	18	3,164
Foreign	(1,222)	(2,112)	2,703
Deferred income tax expense (benefit), total	(8,705)	(19,340)	9,844
Income taxes	$ 28,373	$ 18,956	24,165
Transition tax for accumulated foreign earnings, Income tax benefit			$ 3,900

[1] In 2018, this amount includes $3.9 million of income tax benefit related to a reduction in the 2017 estimate of the one-time transition tax on earnings of foreign subsidiaries enacted by the 2017 Tax Legislation (see discussion below).