Acquisitions (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired	$ 175,083	$ 68,385
Revenue [Abstract]
As reported	1,724,757	1,637,671
Pro forma	1,728,525	1,651,530
Net earnings [Abstract]
As reported	105,705	109,410
Pro forma	$ 107,204	$ 111,953
Basic earnings per share [Abstract]
As reported (in dollars per share)	$ 0.73	$ 0.71
Pro forma (in dollars per share)	0.74	0.72
Diluted earnings per share [Abstract]
As reported (in dollars per share)	0.72	0.70
Pro forma (in dollars per share)	$ 0.73	$ 0.71
Belanger [Member]
Business Acquisition [Line Items]
Current Assets	$ 9,392
Property, Plant, and Equipment	597
Goodwill	97,817
Intangibles	77,000
Other assets and deferred charges	20
Current Liabilities	9,743
Net assets acquired	175,083
Goodwill and intangible assets	174,817
Belanger [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Intangibles	$ 54,500
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	9 years
Belanger [Member] | Patents [Member]
Business Acquisition [Line Items]
Intangibles	$ 16,000
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	9 years
Belanger [Member] | Trademarks [Member]
Business Acquisition [Line Items]
Intangibles	$ 6,500
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	15 years
Ettiingler [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired		$ 53,046
Goodwill		36,505
Intangibles		20,084
Rosario [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Net of Cash Acquired		15,339
Goodwill		$ 10,402
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		10 years
Rosario [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Intangibles		$ 4,149
Minimum [Member] | Ettiingler [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		8 years
Maximum [Member] | Ettiingler [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life		15 years