Supplemental Cash Flow and Other Information - Impairments and Other Non-Cash Charges (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Goodwill and other intangible asset impairments		$ 3,104	$ 70,720
Property, plant and equipment impairments		4,286	2,625
Inventory write-downs		4,075	2,163
Write-off of debt issuance costs on termination of Credit Agreement		1,058	0
Impairments and other non-cash charges	$ 0	$ 12,523	$ 75,508