Revenue (Tables)

3 Months Ended

Mar. 31, 2020

Revenue from Contract with Customer [Abstract]

Schedule of remaining performance obligation

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

(millions) (unaudited)	Remaining Performance Obligations
2019	$	39.5
2020	38.9
2021	22.9
2022	15.9
2023	8.9
2024 and thereafter	6.9
Total	$	133.0

Schedule of contract with customer, asset and liability

The following table provides information about changes to contract liability balances for the three months ended March 31, 2020 and 2019:

	Three Months Ended
(millions) (unaudited)	March 31, 2020			March 31, 2019
Balance, beginning of period	$	(19.4	)	$	(19.1	)
Additional contract liabilities	(13.5		)	(14.3		)
Recognition of revenue from contract liabilities	19.4			19.1
Balance, end of period	$	(13.5	)	$	(14.3	)

The following table provides information about accounts receivable, contract assets and contract liabilities with customers and clients as of March 31, 2020 (unaudited) and December 31, 2019:

(millions)	March 31, 2020			December 31, 2019
Accounts receivable	$	148.6		$	151.3
Contract asset	10.2			11.0
Contract liability	(13.5		)	(19.4		)

The following table provides information about changes to contract asset balances for the three months ended March 31, 2020 and 2019:

	Three Months Ended
(millions) (unaudited)	March 31, 2020			March 31, 2019
Balance, beginning of period	$	11.0		$	11.4
Additional contract assets	10.2			10.3
Reclassification to accounts receivable	(11.0		)	(11.4		)
Balance, end of period	$	10.2		$	10.3

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, 2020 and 2019, respectively. Amortization expense related to cost of contracts for the three months ended March 31, 2020 and 2019 was as follows:

	Three Months Ended
(millions) (unaudited)	March 31, 2020		March 31, 2019
Amortization expense	$	0.4	$	0.5