The expense charged against earnings for the periodic recognition of capitalized leases. This element may apply to energy companies that lease mineral producing properties and to other enterprises that capitalize property, plant, or equipment obtained through capital leases.

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=123406127&loc=d3e45031-112735

Name:	us-gaap_AmortizationOfLeasedAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Leasing Arrangements - Additional Information (Detail) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($) Location	Dec. 31, 2019 USD ($)
Leases [Abstract]
Operating and capital lease agreements lease expiring year			2028		2029
Rent expense	$ 2.7	$ 3.4	$ 8.5	$ 11.0	$ 14.1	$ 14.7
Number of lease agreement terminated locations \| Location					18
Number of reduce footprint lease location \| Location					4
Savings on early lease termination					$ 4.6
Amortization expense for capital leases					$ 0.5	$ 0.7