Goodwill and Long-Lived Assets - Narrative (Details) - USD ($)		3 Months Ended	9 Months Ended	12 Months Ended
	Aug. 31, 2018	Mar. 31, 2018	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill addition				$ 131,509,000	$ 323,000
Goodwill				196,963,000	68,969,000	$ 63,606,000
Gross finite-lived intangible assets				156,703,000	51,992,000
Amortization of intangible assets				9,300,000	4,500,000	1,500,000
Estimated amortization expense for intangible assets in 2019				21,400,000
Estimated amortization expense for intangible assets in 2020				20,800,000
Estimated amortization expense for intangible assets in 2021				16,400,000
Estimated amortization expense for intangible assets in 2022				14,400,000
Estimated amortization expense for intangible assets in 2023				$ 12,700,000
Weighted-average useful life of finite-lived intangible assets				11 years
Carrying value of asset group				$ 872,686,000	560,871,000	527,029,000
Customer relationships
Goodwill [Line Items]
Gross finite-lived intangible assets				141,455,000	39,474,000
Trade names
Goodwill [Line Items]
Gross finite-lived intangible assets				7,235,000	4,288,000
Interface
Goodwill [Line Items]
Goodwill expected to be deductible for income tax purposes			$ 0
Goodwill	$ 130,991,000
Gross finite-lived intangible assets	106,900,000
Interface | Customer relationships
Goodwill [Line Items]
Gross finite-lived intangible assets	$ 103,700,000
Weighted average useful lives of acquired assets	12 years
Interface | Trade names
Goodwill [Line Items]
Gross finite-lived intangible assets	$ 3,200,000
Technical Nonwovens
Goodwill [Line Items]
Goodwill addition				0	323,000
Goodwill				52,337,000	55,662,000	50,829,000
Performance Materials
Goodwill [Line Items]
Goodwill addition			131,500,000	131,509,000	0
Goodwill				$ 144,626,000	$ 13,307,000	$ 12,777,000
Carrying value of asset group		$ 1,300,000
Fair value of assets		500,000
Asset impairment charges		$ 800,000
Performance Materials | Interface
Goodwill [Line Items]
Goodwill addition			$ 131,000,000