Acquisitions (Details) - USD ($) $ in Millions			3 Months Ended	6 Months Ended
	Apr. 01, 2019	Jan. 11, 2019	Sep. 30, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill			$ 1,534.6	$ 1,534.6		$ 1,441.8
Other Long-term Assets
Recognized amounts of identifiable assets acquired and liabilities assumed:
Indemnification asset		$ 5.2
Petersen Aluminum Corporation
Acquisitions
Percentage of ownership interest acquired		100.00%
Total cash consideration transferred		$ 207.2			$ 207.2
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents		5.2	5.2	5.2
Receivables, net		11.5	11.5	11.5
Inventories, net		39.5	39.2	39.2
Prepaid expenses and other current assets		2.1	2.1	2.1
Property, plant and equipment		17.8	17.8	17.8
Definite-lived intangible assets		109.3	110.1	110.1
Other long-term assets		9.5	9.5	9.5
Accounts payable		(5.9)	(5.9)	(5.9)
Income tax payable		1.7	1.7	1.7
Accrued liabilities and other		(8.7)	(8.7)	(8.7)
Other long-term liabilities		(12.4)	(12.4)	(12.4)
Deferred income taxes		(25.4)	(25.6)	(25.6)
Total identifiable net assets		144.2	144.5	144.5
Goodwill		63.0	62.7	62.7
Gross contractual accounts receivable acquired		11.6
Receivables not expected to be collected		0.1
Goodwill deductible for tax purposes		0.0
Indemnification asset		5.2
Petersen Aluminum Corporation | Adjustment
Recognized amounts of identifiable assets acquired and liabilities assumed:
Inventories, net			(0.3)	(0.3)
Definite-lived intangible assets			0.8	0.8
Deferred income taxes			(0.2)	(0.2)
Total identifiable net assets			0.3	0.3
Goodwill			(0.3)	(0.3)
Petersen Aluminum Corporation | Acquired Technology
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangible assets acquired		$ 2.5
Useful life of finite lived intangible assets		10 years
Petersen Aluminum Corporation | Customer relationships
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangible assets acquired		$ 79.7
Useful life of finite lived intangible assets		11 years
Petersen Aluminum Corporation | Trade names
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangible assets acquired		$ 27.9
Useful life of finite lived intangible assets		17 years
MicroConnex Corporation
Acquisitions
Percentage of ownership interest acquired	100.00%
Total cash consideration transferred	$ 46.2
Cash acquired	0.8
Carlisle Construction Materials
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill			595.7	595.7		532.8
Carlisle Construction Materials | Petersen Aluminum Corporation
Acquisitions
Contribution to net sales since acquisition			49.6		133.4
Contribution to operating income since acquisition			4.4		$ 8.0
Carlisle Construction Materials | MicroConnex Corporation
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill deductible for tax purposes	0.0
Carlisle Interconnect Technologies
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill			656.7	656.7		$ 643.1
Carlisle Interconnect Technologies | MicroConnex Corporation
Acquisitions
Contribution to net sales since acquisition			3.5	6.5
Contribution to operating income since acquisition			$ 0.1	$ (0.5)
Recognized amounts of identifiable assets acquired and liabilities assumed:
Receivables, net	3.4
Inventories, net	0.9
Definite-lived intangible assets	27.4
Accounts payable	(0.6)
Deferred income taxes	(7.0)
Goodwill	15.1
Goodwill deductible for tax purposes	$ 0.0
Carlisle Interconnect Technologies | MicroConnex Corporation | Acquired Technology
Recognized amounts of identifiable assets acquired and liabilities assumed:
Useful life of finite lived intangible assets	5 years
Carlisle Interconnect Technologies | MicroConnex Corporation | Customer relationships
Recognized amounts of identifiable assets acquired and liabilities assumed:
Useful life of finite lived intangible assets	12 years
Carlisle Interconnect Technologies | MicroConnex Corporation | Trade names
Recognized amounts of identifiable assets acquired and liabilities assumed:
Useful life of finite lived intangible assets	17 years