New Accounting Standards (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Oct. 01, 2021	Sep. 30, 2021
Liabilities
Long-Term debt	$ 1,027,000		$ 1,008,000
Equity
Additional paid-in capital	761,000		798,000
Retained earnings	$ 1,006,000		935,000
3.25 percent convertible notes due 2037 | Convertible Notes Payable
Equity
Interest rate	3.25%	3.25%
Cumulative Effect, Period of Adoption, Adjustment
Liabilities
Long-Term debt		$ 1,031,000
Equity
Additional paid-in capital		758,000
Retained earnings		$ 952,000
Cumulative Effect, Period of Adoption, Adjustment | Accounting Standards Update 2020-06
Liabilities
Long-Term debt			23,000
Equity
Additional paid-in capital			(40,000)
Retained earnings			$ 17,000