Revenue (Tables)

3 Months Ended

Mar. 31, 2021

Revenue From Contract With Customer [Abstract]

Schedule of Remaining Performance Obligations

The Company expects to recognize the remaining performance obligations as revenue in future periods as follows:

(millions) (unaudited)	Remaining Performance Obligations
2021	$	39.0
2022		30.7
2023		20.8
2024		10.6
2025		4.5
2026 and thereafter		3.3
Total	$	108.9

Schedule of Contract with Customer, Asset and Liabilities

The following table provides information about accounts receivable, contract assets and contract liabilities with customers and clients as of March 31, 2021 (unaudited) and December 31, 2020:

(millions)	March 31, 2021			December 31, 2020
Accounts receivable	$	96.1		$	102.7
Contract asset		6.0			8.6
Contract liability		(8.2	)		(12.5	)

The following table provides information about changes to contract asset balances during the three months ended March 31, 2021 and 2020 (unaudited):

	Three Months Ended
(millions)	March 31, 2021			March 31, 2020
Balance, beginning of period	$	8.6		$	11.0
Additional contract assets		6.0			10.2
Reclassification to accounts receivable		(8.6	)		(11.0	)
Balance, end of period	$	6.0		$	10.2

The following table provides information about changes to contract liability balances during the three months ended March 31, 2021 and 2020 (unaudited):

	Three Months Ended
(millions)	March 31, 2021			March 31, 2020
Balance, beginning of period	$	(12.5	)	$	(19.4	)
Additional contract liabilities		(8.2	)		(13.5	)
Recognition of revenue from contract liabilities		12.5			19.4
Balance, end of period	$	(8.2	)	$	(13.5	)

Schedule of Amortization Expense Related to Cost of Contracts

Amortization expense of cost of contracts related to service concession arrangements within the scope of Topic 853 and certain management type contracts are recorded as a reduction of revenue and were not significant for the three months ended March 31, 2021 and 2020, respectively.  Amortization expense related to cost of contracts for the three months ended March 31, 2021 and 2020 (unaudited) was as follows:

	Three Months Ended
(millions)	March 31, 2021		March 31, 2020
Amortization expense	$	0.3	$	0.4