Acquisitions (Details) - USD ($) $ in Millions					2 Months Ended	3 Months Ended	6 Months Ended		9 Months Ended	10 Months Ended	12 Months Ended
	Jul. 22, 2020	Nov. 20, 2019	Apr. 01, 2019	Jan. 11, 2019	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2020	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2020	Dec. 31, 2019
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill					$ 1,727.3					$ 1,727.3	$ 1,716.3
Other Long-term Assets
Recognized amounts of identifiable assets acquired and liabilities assumed:
Indemnification asset				$ 5.2
Motion Tech Automation, LLC
Acquisitions
Percentage of ownership interest acquired	100.00%
Total cash consideration transferred	$ 33.3
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents	0.3
Goodwill	16.6
Motion Tech Automation, LLC | Customer relationships
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangible assets acquired	$ 1.0
Useful life of finite lived intangible assets	9 years
Motion Tech Automation, LLC | Acquired Technology
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangible assets acquired	$ 2.3
Useful life of finite lived intangible assets	9 years
Motion Tech Automation, LLC | Trade names
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangible assets acquired	$ 1.0
Useful life of finite lived intangible assets	5 years
Providien, LLC
Acquisitions
Total cash consideration transferred		$ 332.1								331.3
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents		3.4			3.4					3.4
Receivables, net		9.8			9.8					9.8
Inventories, net		2.7			2.4					2.4
Contract assets		29.1			29.1					29.1
Prepaid expenses and other current assets		2.3			1.4					1.4
Property, plant and equipment		12.9			12.9					12.9
Definite-lived intangible assets		135.4			132.7					132.7
Other long-term assets		7.1			6.8					6.8
Accounts payable		(6.0)			(5.8)					(5.8)
Income tax payable		(0.7)			0.1					0.1
Accrued and other current liabilities		(7.0)			(7.0)					(7.0)
Other long-term liabilities		(8.1)			(7.0)					(7.0)
Deferred income taxes		(27.1)			(19.0)					(19.0)
Total identifiable net assets		153.8			159.8					159.8
Receivables not expected to be collected		0.1
Goodwill deductible for tax purposes		66.5
Finite-lived intangible assets acquired		132.6
Providien, LLC | Adjustment
Acquisitions
Total cash consideration transferred										(0.8)
Recognized amounts of identifiable assets acquired and liabilities assumed:
Inventories, net					(0.3)					(0.3)
Prepaid expenses and other current assets					(0.9)					(0.9)
Definite-lived intangible assets					(2.7)					(2.7)
Other long-term assets					(0.3)					(0.3)
Accounts payable					0.2					0.2
Income tax payable					0.8					0.8
Other long-term liabilities					1.1					1.1
Deferred income taxes					8.1					8.1
Total identifiable net assets					6.0					6.0
Providien, LLC | Customer relationships
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangible assets acquired		$ 108.7
Useful life of finite lived intangible assets		14 years
Providien, LLC | Acquired Technology
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangible assets acquired		$ 19.5
Useful life of finite lived intangible assets		7 years
Providien, LLC | Trade names
Recognized amounts of identifiable assets acquired and liabilities assumed:
Finite-lived intangible assets acquired		$ 4.4
Useful life of finite lived intangible assets		2 years
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
Receivables, net				11.5							11.5
Inventories, net				39.5							39.2
Prepaid expenses and other current assets				2.1							2.1
Property, plant and equipment				17.8							17.8
Definite-lived intangible assets				109.3							110.1
Other long-term assets				9.5							9.5
Accounts payable				(5.9)							(5.9)
Income tax payable				1.7							1.7
Accrued and other current liabilities				(8.7)							(8.7)
Other long-term liabilities				(12.4)							(12.5)
Deferred income taxes				(25.4)							(25.6)
Total identifiable net assets				144.2							144.4
Goodwill				63.0							62.8
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
Release of indemnification asset related to escrow expirations							$ 3.0
Petersen Aluminum Corporation | Adjustment
Recognized amounts of identifiable assets acquired and liabilities assumed:
Inventories, net											(0.3)
Definite-lived intangible assets											0.8
Other long-term liabilities											(0.1)
Deferred income taxes											(0.2)
Total identifiable net assets											0.2
Goodwill											(0.2)
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 | 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 | 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
Recognized amounts of identifiable assets acquired and liabilities assumed:
Cash and cash equivalents			0.8
Carlisle Interconnect Technologies
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill					829.3					829.3	835.2
Carlisle Interconnect Technologies | Motion Tech Automation, LLC
Acquisitions
Contribution to net sales since acquisition					4.1
Contribution to operating income since acquisition					0.1
Recognized amounts of identifiable assets acquired and liabilities assumed:
Receivables, net	$ 2.8
Inventories, net	4.3
Definite-lived intangible assets	4.3
Accounts payable	(1.3)
Goodwill	2.8
Maximum indemnification	1.6
Indemnification asset	1.5
Carlisle Interconnect Technologies | Providien, LLC
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill		$ 178.3			171.5					171.5
Carlisle Interconnect Technologies | Providien, LLC | Adjustment
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill					(6.8)					(6.8)
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			15.2
Goodwill deductible for tax purposes			$ 0.0
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 | 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 | Trade names
Recognized amounts of identifiable assets acquired and liabilities assumed:
Useful life of finite lived intangible assets			17 years
Carlisle Construction Materials
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill					610.9					610.9	597.1
Carlisle Construction Materials | Motion Tech Automation, LLC
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill	11.0
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 Fluid Technologies
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill					$ 190.6					$ 190.6	$ 187.5
Carlisle Fluid Technologies | Motion Tech Automation, LLC
Recognized amounts of identifiable assets acquired and liabilities assumed:
Goodwill	$ 2.8