Debt - Additional Information (Detail)			2 Months Ended	3 Months Ended				9 Months Ended	12 Months Ended	13 Months Ended	14 Months Ended	19 Months Ended
	Mar. 13, 2019 USD ($) Aircraft	Sep. 28, 2018 USD ($)	Mar. 13, 2023	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Mar. 31, 2019 USD ($)	Sep. 30, 2021	Dec. 30, 2022	Mar. 31, 2020	Mar. 13, 2023	Sep. 30, 2020	Dec. 31, 2018 USD ($)	Mar. 17, 2014 USD ($)
Debt Instrument [Line Items]
Letters of credit outstanding under the facility							$ 19,800,000						$ 19,800,000
Long-term Debt, Gross							$ 700,000,000						630,000,000
Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 70,000,000
Number of Aircraft Securing Debt Agreement | Aircraft	91
Debt covenant, minimum unrestricted cash requirement at the end of each calendar month	$ 20,000,000
Debt covenant, minimum cash and cash equivalents held solely by the Company and guarantors	$ 10,000,000
Debt covenant, appraisal ratio of aircraft collateral at quarter end	4.00
Event of default, judgments (in excess of)	$ 2,500,000
Event of default, ERISA event liabilities (in excess of)	2,500,000
Event of default, impairments of collateral (in excess of)	$ 2,500,000
5.25% Senior Notes due March 15, 2019 [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Interest rate on debt							5.25%							5.25%
Maturity date of Senior notes payable							Mar. 15, 2019
Debt instrument interest rate term							Interest is payable semi-annually on March 15 and September 15 of each year.
Debt instrument restrictive covenants							The indenture governing the 2019 Notes (the “2019 Indenture”) contains, among other things, certain restrictive covenants, including limitations on incurring indebtedness, creating liens, selling assets and entering into certain transactions with affiliates. The covenants also limit PHI’s ability to, among other things, pay cash dividends on common stock, repurchase or redeem common or preferred equity, prepay subordinated debt and make certain investments.
Related party term loan, amount issued														$ 500,000,000
Long-term Debt, Gross							$ 500,000,000						500,000,000
6% Related Party Term Loan [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Interest rate on debt							6.00%
Related party term loan, amount issued		$ 130,000,000
Proceeds from related party debt		130,000,000
Long-term Debt, Gross							$ 130,000,000						130,000,000
Letter of Credit to Secure workers Compensation Policies, Air Medical License, and a Traditional Provider Contract [Member]
Debt Instrument [Line Items]
Letters of credit outstanding under the facility							12,200,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Repayments of senior secured revolving credit facility, including accrued interest		$ 122,700,000
Letters of credit outstanding under the facility							$ 7,600,000						$ 70,000,000
London Interbank Offered Rate (LIBOR) [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	6.00%
Base Rate [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	5.00%
Scenario, Forecast [Member] | Term Loan [Member]
Debt Instrument [Line Items]
Debt covenant, minimum fixed charge ratio at the end of each test period				0.9125	0.3750	0.1875				0	1.2000
Debt covenant, secured leverage ratio, at test period end			3.75					4.25	4.00			4.50