Income Tax Matters - Reconciliation of Income Tax Benefit (Provision) based on Effective Income Tax Rate and Statutory Tax Rate (Parenthetical) (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reconciliation between income tax provision and statutory income tax provision:
(Increase) decrease in federal valuation allowances	$ (0.2)	$ 0.0	$ 0.1
State and Local Jurisdiction
Reconciliation between income tax provision and statutory income tax provision:
(Increase) decrease in federal valuation allowances	1.6	3.5	(1.4)
State and tax expense (benefit) before adjustments	(0.7)	1.3	3.8
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	$ 1.3	$ 3.7	$ (0.7)

State income tax expense benefit before rate reconciliation adjustments.

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- References

No definition available.

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- Definition

Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to increase (decrease) in the valuation allowance for deferred tax assets.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32687-109319

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- Definition

Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations, attributable to increase (decrease) in the income tax rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=123427490&loc=d3e32059-109318

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32687-109319

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