Leases - Components of Lease Expense (Detail) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Finance lease cost:
Amortization of right-of-use assets	$ 1.0	$ 1.7
Interest on lease liabilities	0.0	0.0
Total finance lease cost	1.0	1.7
Operating lease cost	12.8	12.1
Short-term lease cost	3.2	2.5
Variable lease cost	0.3	0.3
Total lease cost	$ 17.3	$ 16.6

Finance lease cost.

No definition available.

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Balance Type:	debit
Period Type:	duration

- Definition

Amount of interest expense on finance lease liability.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
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-URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918686-209980

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-Publisher FASB
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-URI http://asc.fasb.org/extlink&oid=121568110&loc=SL77918982-209971

+ Details

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- Definition

Amount of amortization expense attributable to right-of-use asset from finance lease.

+ References

+ Details

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Balance Type:	debit
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- Definition

Amount of lease cost recognized by lessee for lease contract.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
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-URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918686-209980

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+ Details

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- References

No definition available.

+ Details

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- Definition

Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 55
-Paragraph 53
-URI http://asc.fasb.org/extlink&oid=121568110&loc=SL77918982-209971

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-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=121609121&loc=SL77918686-209980

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- Definition

Amount of short-term lease cost, excluding expense for lease with term of one month or less.

+ References

+ Details

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- Definition

Amount of variable lease cost, excluded from lease liability, recognized when obligation for payment is incurred for finance and operating leases.

+ References

+ Details

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