Subsequent Events - Additional Information (Detail)					3 Months Ended		9 Months Ended
	Oct. 16, 2018 $ / shares	Oct. 02, 2018 USD ($)	Oct. 01, 2018 USD ($) Company Director $ / shares shares	Sep. 26, 2018 USD ($)	Sep. 30, 2018 USD ($) $ / shares shares	Sep. 30, 2017 $ / shares	Sep. 30, 2018 USD ($) $ / shares shares	Sep. 30, 2017 $ / shares	Dec. 31, 2018 USD ($)	Dec. 31, 2017 shares
Subsequent Event [Line Items]
Cash dividends declared (in USD per share) | $ / shares					$ 0.17	$ 0.17	$ 0.51	$ 0.49
Common stock, shares authorized (in shares) | shares					90,000,000		90,000,000			90,000,000
Business acquisition-related costs					$ 4,600,000		$ 11,800,000
Cross Currency Interest Rate Swap [Member]
Subsequent Event [Line Items]
Short term derivative liabilities					$ 14,800,000		$ 14,800,000
6.125% Senior Notes Due 2026 [Member] | Newco [Member]
Subsequent Event [Line Items]
Debt instrument, aggregate principal amount				$ 400,000,000
Debt instrument, interest rate percentage				6.125%
Debt instrument, maturity year				2026
Fortive [Member] | Scenario Forecast [Member]
Subsequent Event [Line Items]
Business acquisition, non-recurring implementation costs									$ 24,000,000
Fortive [Member] | Minimum [Member] | Scenario Forecast [Member]
Subsequent Event [Line Items]
Business acquisition, transaction-related costs									85,000,000
Business acquisition, transaction-related costs capitalized									45,000,000
Fortive [Member] | Maximum [Member] | Scenario Forecast [Member]
Subsequent Event [Line Items]
Business acquisition, transaction-related costs									95,000,000
Business acquisition, transaction-related costs capitalized									$ 50,000,000
Subsequent Event [Member]
Subsequent Event [Line Items]
Cash dividends declared (in USD per share) | $ / shares	$ 0.17
Dividend declaration date	Oct. 16, 2018
Dividend payable date	Jan. 03, 2019
Dividend record date	Dec. 17, 2018
Common stock, shares authorized (in shares) | shares			120,000,000
Number of Board of Directors elected | Director			1
Subsequent Event [Member] | Cross Currency Interest Rate Swap Effective Period of Swap December Twenty Three Two Thousand Sixteen To December Thirty One Two Thousand Nineteen [Member]
Subsequent Event [Line Items]
Derivative notional amount terminated		$ 100,000,000
Subsequent Event [Member] | Cross Currency Interest Rate Swap Effective Period of Swap December Twenty Three Two Thousand Sixteen To December Thirty One Two Thousand Eighteen [Member]
Subsequent Event [Line Items]
Derivative notional amount terminated		40,000,000
Subsequent Event [Member] | Cross Currency Interest Rate Swap [Member]
Subsequent Event [Line Items]
Derivative termination fees paid		$ 14,000,000
Subsequent Event [Member] | Altra Term Loan Facility [Member]
Subsequent Event [Line Items]
Debt instrument, term			7 years
Maximum amount available			$ 1,340,000,000
Debt instrument, description of variable rate basis			At Altra’s option, borrowings under the Altra Term Loan Facility will bear interest at a per annum rate equal to a “Eurocurrency Rate” plus 2.00%, in the case of Eurocurrency Rate borrowings, or equal to a “Base Rate” plus 1.00%, in the case of Base Rate borrowings.
Subsequent Event [Member] | Altra Term Loan Facility [Member] | Eurocurrency Rate [Member]
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate			2.00%
Subsequent Event [Member] | Altra Term Loan Facility [Member] | Base Rate [Member]
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate			1.00%
Subsequent Event [Member] | Altra Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Debt instrument, term			5 years
Maximum amount available			$ 300,000,000
Debt instrument, description of variable rate basis			At the applicable borrower’s option, borrowings under the Altra Revolving Credit Facility will initially bear interest at a per annum rate equal to a Eurocurrency Rate plus 2.00%, in the case of Eurocurrency Rate borrowings, or equal to a Base Rate plus 1.00%, in the case of Base Rate borrowings
Credit facility, commitment fee description			Altra will be required to pay fees that will fluctuate between 0.250% per annum to 0.375% per annum on the unused amount of the Altra Revolving Credit Facility, based upon Altra’s senior secured net leverage ratio.
Subsequent Event [Member] | Altra Revolving Credit Facility [Member] | Eurocurrency Rate [Member]
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate			2.00%
Subsequent Event [Member] | Altra Revolving Credit Facility [Member] | Base Rate [Member]
Subsequent Event [Line Items]
Debt instrument, basis spread on variable rate			1.00%
Subsequent Event [Member] | Altra Revolving Credit Facility [Member] | Minimum [Member]
Subsequent Event [Line Items]
Credit facility, unused capacity, commitment fee percentage			0.25%
Subsequent Event [Member] | Altra Revolving Credit Facility [Member] | Maximum [Member]
Subsequent Event [Line Items]
Credit facility, unused capacity, commitment fee percentage			0.375%
Subsequent Event [Member] | 6.125% Senior Notes Due 2026 [Member] | Newco [Member]
Subsequent Event [Line Items]
Debt instrument, maturity date			Oct. 01, 2026
Debt instrument, interest payment terms			Interest on the Notes accrues from October 1, 2018, and the first interest payment date on the Notes will be April 1, 2019.
Debt instrument, first interest payment date			Apr. 01, 2019
Debt instrument, redemption, description			The Notes may be redeemed at the option of Newco on or after October 1, 2023, in the manner and at the redemption prices specified in the indenture governing the Notes, plus accrued and unpaid interest thereon, if any, to, but excluding, the date of redemption.
Debt instrument, redemption period, start date			Oct. 01, 2023
Subsequent Event [Member] | Primary Notes [Member] | Newco [Member]
Subsequent Event [Line Items]
Debt instrument, aggregate principal amount			$ 150,000,000
Subsequent Event [Member] | Selling Securityholder Notes [Member] | Newco [Member]
Subsequent Event [Line Items]
Debt instrument, aggregate principal amount			$ 250,000,000
Subsequent Event [Member] | Merger Shareholders [Member]
Subsequent Event [Line Items]
Ownership percentage on outstanding shares of common stock			54.00%
Subsequent Event [Member] | Pre-Merger Shareholders [Member]
Subsequent Event [Line Items]
Ownership percentage on outstanding shares of common stock			46.00%
Subsequent Event [Member] | Fortive [Member]
Subsequent Event [Line Items]
Business combination, number of operating companies in transaction | Company			4
Subsequent Event [Member] | Newco [Member]
Subsequent Event [Line Items]
Business acquisition, equity interest issued or issuable, number of shares | shares			35,000,000
Subsequent Event [Member] | A&S Business [Member]
Subsequent Event [Line Items]
Business combination, aggregate purchase price			$ 2,855,700,000
Business combination, cash and debt instruments			1,400,000,000
Business combination, shares of common stock issued, value			$ 1,455,700,000
Business combination, closing stock price per share | $ / shares			$ 41.59