Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Name:	us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Net Income Per Common Share (Narrative) (Details) - Stock Units [Member] - shares		12 Months Ended
	Apr. 30, 2021	Dec. 31, 2023	Dec. 31, 2022
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares included in the computation of diluted earnings per share (in shares)		0	0
Old Frontier Director And Employee Compensation Plans [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares included in the computation of diluted earnings per share (in shares)	339,544