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Represents the discount on issuance of debt.

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Percentage of discount on issuance.

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Amount before tax of foreign currency transaction unrealized gain (loss) on 2024 Euro notes recognized in the income statement.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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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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Percentage of principal amount of debt redeemed.

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Foreign exchange rate used to translate amounts denominated in functional currency to reporting currency.

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Amount before tax of foreign currency transaction realized gain (loss) recognized in the income statement.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Long-term debt: (Details) $ in Thousands, € in Millions		1 Months Ended				3 Months Ended		9 Months Ended
Long-term debt: (Details) $ in Thousands, € in Millions	Jun. 09, 2020 USD ($) $ / €	May 31, 2021 USD ($)	Jun. 30, 2020 USD ($) $ / €	Jun. 30, 2020 EUR (€)	Jun. 30, 2019 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 EUR (€)	May 07, 2021 USD ($)	Mar. 31, 2021 USD ($)	Jun. 30, 2020 EUR (€) $ / €	Jun. 30, 2019 EUR (€)	Jun. 25, 2019 EUR (€)
Long-term debt
Realized foreign exchange gain on issuance on 2024 Euro Notes									$ 2,547
Foreign Currency Transaction Gain Loss Unrealized On 2024 Euro Notes						$ 10,169	$ (17,315)	$ 23,759	(17,827)
Net proceeds from issuance of senior unsecured 2024 Euro Notes					$ 152,100
Interest Rate Swap
Long-term debt
Interest expense						3,100		3,100
Senior unsecured 2024 Notes
Long-term debt
Face amount						$ 405,600		$ 405,600		€ 350.0			€ 215.0	€ 135.0	€ 135.0
Interest rate (as a percent)			4.375%			4.375%		4.375%		4.375%			4.375%
Discount rate (as a percent)			99.50%	99.50%
Original amount issued at a discount			$ 240,000										€ 213.9
Foreign currency exchange rate at Euro to USD \| $ / €	1.133		1.112										1.112
Realized foreign exchange gain on issuance on 2024 Euro Notes	$ 2,500
Foreign Currency Transaction Gain Loss Unrealized On 2024 Euro Notes						$ 10,200	$ 17,300	$ 23,800	17,800
Net proceeds from issuance of senior unsecured 2024 Euro Notes			$ 240,300	€ 215.0					240,285
Debt costs									$ 2,137
Senior unsecured 2021 notes
Long-term debt
Face amount			$ 189,200
Interest rate (as a percent)			5.625%										5.625%
Senior secured 2026 Notes
Long-term debt
Face amount						$ 500,000		$ 500,000			$ 500,000
Interest rate (as a percent)						3.50%		3.50%		3.50%
Proceeds from Issuance of Secured Debt								$ 496,933
Discount on issuance of debt								1,800
Debt costs								$ 1,317
Redemption price percentage of principal amount redeemed								100.00%
Senior secured notes due 2022
Long-term debt
Face amount						$ 284,100		$ 284,100				$ 115,900
Interest rate (as a percent)		5.375%
Senior secured debt outstanding		$ 284,100
Redemption of debt		$ 45,000
Redemption price percentage of principal amount redeemed								100.00%
Interest amount deposited with trustee								$ 11,500
Senior secured notes due 2022 \| Interest Rate Swap
Long-term debt
Face amount						$ 3,100		$ 3,100