Acquisitions - Narrative (Details) - USD ($)		3 Months Ended		9 Months Ended		12 Months Ended
	Jul. 12, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2016	Aug. 31, 2018	Aug. 30, 2018	Jul. 06, 2016
Business Acquisition [Line Items]
Business acquisitions, net of cash acquired				$ 269,972,000	$ 335,000
Revolving Credit Facility | Amended Credit Facility
Business Acquisition [Line Items]
Maximum borrowing capacity		$ 450,000,000.0		450,000,000.0			$ 450,000,000	$ 175,000,000	$ 450,000,000
Interface
Business Acquisition [Line Items]
Voting interest acquired (as a percent)						100.00%
Business acquisitions, net of cash acquired						$ 268,400,000
Cash acquired from acquisition						5,200,000
Purchase price borrowings						$ 261,400,000.0
Transaction and acquisition related costs		1,500,000		2,600,000
Net sales of acquiree since acquisition date		11,800,000		11,800,000
Operating income of acquiree since acquisition date		300,000		300,000
Purchase accounting inventory fair value step-up adjustment		1,400,000		1,400,000
Intangible amortization expense		900,000		900,000
Additional pro-forma net income (loss)		$ 7,900,000	$ (1,700,000)	$ 5,600,000	$ (11,600,000)
Precision Filtration Division of Precision Custom Coatings
Business Acquisition [Line Items]
Payments to acquire business	$ 1,600,000
Post closing working capital adjustment	$ 2,000,000