Acquisitions - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
	May 20, 2019	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired										$ 0	$ 33,196	$ 0
Estimated amortization period										14 years
Goodwill		$ 443,272				$ 436,679				$ 443,272	436,679	413,640
Strategic transaction costs (Note 13)										717	4,400	421
Revenues		388,248	$ 304,392	$ 314,438	$ 341,145	375,254	$ 351,014	$ 349,675	$ 326,038	1,348,223	1,401,981	1,358,104
Net income (loss)										120,101	136,440	124,150
Depreciation										27,700	26,500	26,900
Amortization primarily related to intangible assets										11,570	11,119
Americas
Business Acquisition [Line Items]
Goodwill		293,200								293,200
Revenues										874,305	915,118	$ 854,287
Sierra Monitor Corporation
Business Acquisition [Line Items]
Common stock acquired (as a percent)	100.00%
Payments to Acquire Businesses, Net of Cash Acquired	$ 33,200
Future amortization expense, year one		1,000								1,000
Future amortization expense, year two		1,000								1,000
Future amortization expense, year three		1,000								1,000
Finite-Lived Intangible Assets, Amortization Expense, Year Four		1,000								1,000
Future amortization expense, year five		$ 1,000								1,000
Step up to fair value of acquired inventory as part of purchase price allocation	1,600
Goodwill	19,900
Revenues										21,200
Net income (loss)										2,800
Purchase accounting amortization for intangible assets and inventory step up excluded from acquisitions										1,200	2,600
Business Acquisition, Transaction Costs						$ 2,200					2,200
Net income related to acquiree adjusted to remove transaction costs										$ 3,800	1,500
Sierra Monitor Corporation | Americas
Business Acquisition [Line Items]
Goodwill	$ 19,900
Globe Holding Company LLC
Business Acquisition [Line Items]
Revenues											13,500
Net income (loss)											(3,300)
Technology related assets
Business Acquisition [Line Items]
Estimated amortization period										8 years
Technology related assets | Sierra Monitor Corporation
Business Acquisition [Line Items]
Estimated amortization period	5 years
Customer-related intangibles | Sierra Monitor Corporation
Business Acquisition [Line Items]
Estimated amortization period	10 years
Stock Options And Restricted Stock Units | Sierra Monitor Corporation
Business Acquisition [Line Items]
Goodwill	$ 900
Performance Stock | Sierra Monitor Corporation
Business Acquisition [Line Items]
Share-based Payment Arrangement, Expense											$ 1,500