Debt (Summary of Senior Notes) (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Net premiums, discounts, and issuance costs (b)	$ (8,465)	$ (9,701)
Total senior notes	1,926,535	1,990,299
Other notes payable	54,780	55,228
Notes payable	1,981,315	2,045,527
Estimated fair value	$ 1,998,032	2,079,218
Senior Notes | 5.500% unsecured senior notes due March 2026
Debt Instrument [Line Items]
Stated interest rate	5.50%
Face amount	$ 478,000	500,000
Senior Notes | 5.000% unsecured senior notes due January 2027
Debt Instrument [Line Items]
Stated interest rate	5.00%
Face amount	$ 457,000	500,000
Senior Notes | 7.875% unsecured senior notes due June 2032
Debt Instrument [Line Items]
Stated interest rate	7.875%
Face amount	$ 300,000	300,000
Senior Notes | 6.375% unsecured senior notes due May 2033
Debt Instrument [Line Items]
Stated interest rate	6.375%
Face amount	$ 400,000	400,000
Senior Notes | 6.000% unsecured senior notes due February 2035
Debt Instrument [Line Items]
Stated interest rate	6.00%
Face amount	$ 300,000	$ 300,000