Acquisitions - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended
	May 20, 2019	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill		$ 430,114		$ 436,679
Revenues		341,145	$ 326,038
Net income (loss)		43,674	23,232
Sierra Monitor Corporation
Business Acquisition [Line Items]
Voting interest acquired (percentage)	100.00%
Payments to acquire businesses	$ 33,200
Goodwill	19,900	19,900
Estimated future amortization expense, remainder of fiscal year		900
Estimated future amortization, years two through four		1,200
Estimated future amortization expense, year 4		1,100
Estimated future amortization expense, thereafter		4,200
Step up to fair value of acquired inventory	$ 1,600
Amortization expense related to step up to fair value of acquired inventory		400
Transaction costs		900
Revenues		5,700
Net income (loss)		500
Transaction costs		$ 100	$ 500
Customer relationships | Sierra Monitor Corporation
Business Acquisition [Line Items]
Useful life	10 years
Technology | Sierra Monitor Corporation
Business Acquisition [Line Items]
Useful life	5 years
Stock Options And Restricted Stock Units | Sierra Monitor Corporation
Business Acquisition [Line Items]
Goodwill	$ 900