Business Segments - Sales by Geographical Location (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues from External Customers and Long-Lived Assets
Net Sales	$ 115,576	$ 118,365	$ 141,563	$ 121,907	$ 141,331	$ 144,848	$ 190,701	$ 139,548	$ 497,411	$ 616,428	$ 581,064
United States
Revenues from External Customers and Long-Lived Assets
Net Sales									398,288	490,735	439,002
United Kingdom
Revenues from External Customers and Long-Lived Assets
Net Sales									44,643	41,879	66,451
Canada
Revenues from External Customers and Long-Lived Assets
Net Sales									34,498	57,574	42,810
Other
Revenues from External Customers and Long-Lived Assets
Net Sales									$ 19,982	$ 26,241	$ 32,800