Debt (Schedule of Obligations Under Debt Arrangements) (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Principal	$ 3,405,743	$ 3,431,302
Unamortized Debt Issuance Costs	35,481	37,586
Net Value	3,370,262	3,393,716
Senior secured credit facility
Debt Instrument [Line Items]
Principal	699,000	643,700
Unamortized Debt Issuance Costs	0	0
Net Value	699,000	643,700
Unamortized debt issuance costs included in other long term debt assets	$ 4,800	$ 5,800
6.000% senior unsecured notes due 2023
Debt Instrument [Line Items]
Senior unsecured notes, stated rate	600.00%	600.00%
Principal	$ 0	$ 80,859
Unamortized Debt Issuance Costs	0	504
Net Value	$ 0	$ 80,355
5.625% senior unsecured notes due 2024
Debt Instrument [Line Items]
Senior unsecured notes, stated rate	562.50%	562.50%
Principal	$ 341,135	$ 341,135
Unamortized Debt Issuance Costs	2,749	2,963
Net Value	$ 338,386	$ 338,172
6.500% senior unsecured notes due 2025
Debt Instrument [Line Items]
Senior unsecured notes, stated rate	650.00%	650.00%
Principal	$ 534,834	$ 534,834
Unamortized Debt Issuance Costs	5,343	5,639
Net Value	$ 529,491	$ 529,195
6.250% senior unsecured notes due 2026
Debt Instrument [Line Items]
Senior unsecured notes, stated rate	625.00%	625.00%
Principal	$ 359,799	$ 359,799
Unamortized Debt Issuance Costs	3,994	4,189
Net Value	$ 355,805	$ 355,610
8.000% senior unsecured notes due 2027
Debt Instrument [Line Items]
Senior unsecured notes, stated rate	800.00%	800.00%
Principal	$ 750,000	$ 750,000
Unamortized Debt Issuance Costs	12,524	13,022
Net Value	$ 737,476	$ 736,978
7.750% senior unsecured notes due 2028
Debt Instrument [Line Items]
Senior unsecured notes, stated rate	775.00%	775.00%
Principal	$ 720,975	$ 720,975
Unamortized Debt Issuance Costs	10,871	11,269
Net Value	$ 710,104	$ 709,706

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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