Accumulated Other Comprehensive Loss - Summary of Changes in Accumulated Other Comprehensive Loss by Component (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss) before reclassifications	$ (22.1)	$ 5.8
Amounts reclassified from accumulated other comprehensive loss	0.5	1.0
Net current-period other comprehensive income (loss)	(21.6)	6.8
Unrealized Translation Adjustments
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	9.8	(10.6)
Adoption of new accounting standard			$ 0.0
Adjusted beginning balance			(10.6)
Other comprehensive income (loss) before reclassifications	(22.1)	5.8
Amounts reclassified from accumulated other comprehensive loss	0.0	0.0
Net current-period other comprehensive income (loss)	(22.1)	5.8
Less: other comprehensive income attributable to redeemable non-controlling interests	0.9
Net current-period other comprehensive income (loss) attributable to EnPro Industries, Inc.	(23.0)
Ending balance	(13.2)	(4.8)
Pension and Other Postretirement Plans
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(46.2)	(34.9)
Adoption of new accounting standard			(11.5)
Adjusted beginning balance			(46.4)
Other comprehensive income (loss) before reclassifications	0.0	0.0
Amounts reclassified from accumulated other comprehensive loss	0.5	1.0
Net current-period other comprehensive income (loss)	0.5	1.0
Less: other comprehensive income attributable to redeemable non-controlling interests	0.0
Net current-period other comprehensive income (loss) attributable to EnPro Industries, Inc.	0.5
Ending balance	(45.7)	(45.4)
Accumulated Other Comprehensive Loss
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(36.4)	(45.5)
Adoption of new accounting standard			(11.5)
Adjusted beginning balance			$ (57.0)
Net current-period other comprehensive income (loss)	(22.5)	6.8
Less: other comprehensive income attributable to redeemable non-controlling interests	0.9
Net current-period other comprehensive income (loss) attributable to EnPro Industries, Inc.	(22.5)
Ending balance	$ (58.9)	$ (50.2)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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Amount after tax, before reclassification adjustments of other comprehensive income (loss).

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Amount of stockholders' equity including the portion attributable to noncontrolling interests, after the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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