The amount of forward loss reserve for commercial power-by-the-hour.

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Amount of expense for expected loss on commercial power by hour contract.

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The amount of contract with customer asset after reducing liabilities.

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Amount of increase (decrease) in contract with customer assets (liabilities) net.

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Amount of increase (decrease) in obligation to transfer good or service to customer for which consideration has been received or is receivable classified as noncurrent.

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Amount of increase (decrease) in obligation to transfer good or service to customer for which consideration from customer has been received or is due, other.

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Total contract with customer liability revenue recognized during the period, including revenue recognized from current period increase in the contract liability.

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Amount of allowance for credit loss on accounts receivable.

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Amount of allowance for credit loss on accounts receivable, classified as current.

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Amount of expense (reversal of expense) for expected credit loss on right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

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Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as current.

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Amount of deferred income and obligation to transfer product and service to customer for which consideration has been received or is receivable, classified as current.

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Amount of deferred income and obligation to transfer product and service to customer for which consideration has been received or is receivable, classified as noncurrent.

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Revenue Recognition - Contract Assets and Liabilities and Remaining Performance Obligations (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Feb. 28, 2021	Nov. 30, 2020	Aug. 31, 2020	Feb. 29, 2020	Feb. 28, 2021	Feb. 29, 2020	May 31, 2020
Contract Assets and Liabilities
Contract assets - current	$ 62.1				$ 62.1		$ 49.3
Contract assets - non-current	23.9				23.9		22.4
Contract liabilities:
Deferred revenue - current	(19.8)				(19.8)		(11.2)
Deferred revenue on long-term contracts	(18.5)				(18.5)		(88.0)
Net contract assets (liabilities)	47.7				47.7		(27.5)
Change in contract assets - current					12.8
Change in contract assets - non-current					1.5
Change in contract liabilities - current					(8.6)
Change in contract liabilities - non-current					69.5
Change in net contract assets (liabilities)					75.2
Charge related to terminiation of PBH customer contract			$ 2.2
Charge related to loss on contract charge	3.5
PBH forward loss reserve	2.4				2.4
Forward loss reserves	8.7				8.7
Forward loss reserves classified as current in accrued liabilities	16.9				16.9		$ 22.1
Change in Contract with Customer, Liability
Deferred revenue at beginning of period	(48.4)		$ (99.2)	$ (133.8)	(99.2)	$ (96.4)
Revenue deferred	(61.7)			(102.1)	(184.7)	(342.4)
Revenue recognized	72.4			121.7	248.5	326.0
Other	(0.6)			(0.5)	(2.9)	(1.9)
Deferred revenue at end of period	(38.3)	$ (48.4)		$ (114.7)	(38.3)	$ (114.7)
Remaining Performance Obligations
Remaining performance obligation	$ 700.0				$ 700.0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-02-28
Remaining Performance Obligations
Remaining performance obligation (as a percent)	50.00%				50.00%
Expected timing of satisfaction of remaining performance obligation	12 months				12 months
Accrued liabilities
Contract liabilities:
PBH forward loss reserve	$ 2.1				$ 2.1
Other liabilities
Contract liabilities:
PBH forward loss reserve	$ 0.3				$ 0.3
PBH contracts
Contract liabilities:
Contract Charges on non-achievement of minimum volume guarantees		$ 4.5