Acquisitions - Additional Information (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
	May 20, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Business Acquisition [Line Items]
Acquisition, net of cash acquired (Note 19)				$ 0	$ 33,196
Goodwill		$ 430,671		430,671		$ 436,679
Revenues		314,438	$ 349,675	655,583	675,713
Net income (loss)		36,066	39,806	79,741	63,038
Sierra Monitor Corporation
Business Acquisition [Line Items]
Voting interest acquired (percentage)	100.00%
Acquisition, net of cash acquired (Note 19)	$ 33,200
Goodwill	19,900	19,900		19,900
Estimated future amortization expense, remainder of fiscal year		600		600
Estimated future amortization, years two through four		1,200		1,200
Estimated future amortization expense, year 4		1,100		1,100
Estimated future amortization expense, thereafter		4,200		4,200
Step up to fair value of acquired inventory	$ 1,600
Amortization expense related to step up to fair value of acquired inventory				600
Transaction costs				2,000
Revenues				11,100
Net income (loss)				1,400
Transaction costs		$ 200	$ 2,000	$ 200	$ 2,000
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