Senior Unsecured Notes (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Jun. 23, 2021	Dec. 31, 2020
Senior Notes [Line Items]
Unsecured Long-term Debt, Noncurrent	$ 1,671,818		$ 1,660,663
6.125% Senior Unsecured Notes due 2022 [Member]
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	6.125%		6.125%
Senior Notes, Principal amount	$ 0		$ 212,403
Senior Notes, unamortized deferred financing costs	0		855
Unsecured Long-term Debt, Noncurrent	$ 0		$ 211,548
5.0% Senior Unsecured Notes due 2024 [Member]
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	5.00%		5.00%
Senior Notes, Principal amount	$ 104,769		$ 277,034
Senior Notes, unamortized deferred financing costs	499		1,576
Unsecured Long-term Debt, Noncurrent	$ 104,270		$ 275,458
5.625% Senior Unsecured Notes due 2025 [Member]
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	5.625%		5.625%
Senior Notes, Principal amount	$ 349,118		$ 349,118
Senior Notes, unamortized deferred financing costs	2,476		2,792
Unsecured Long-term Debt, Noncurrent	$ 346,642		$ 346,326
6.75% Senior Unsecured Notes due 2026 [Member]
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	6.75%		6.75%
Senior Notes, Principal amount	$ 419,235		$ 419,235
Senior Notes, unamortized deferred financing costs	3,620		3,970
Unsecured Long-term Debt, Noncurrent	$ 415,615		$ 415,265
6.625% Senior Unsecured Notes due 2027 [Member]
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	6.625%		6.625%
Senior Notes, Principal amount	$ 416,791		$ 416,791
Senior Notes, unamortized deferred financing costs	4,337		4,725
Unsecured Long-term Debt, Noncurrent	$ 412,454		412,066
6.5% Senior Unsecured Notes Due 2028 [Member]
Senior Notes [Line Items]
Senior Notes, interest rate, stated percentage	6.50%	6.50%
Senior Notes, Principal amount	$ 400,000	$ 400,000	0
Senior Notes, unamortized deferred financing costs	7,163		0
Unsecured Long-term Debt, Noncurrent	392,837		0
Senior Unsecured Notes [Member]
Senior Notes [Line Items]
Senior Notes, Principal amount	1,689,913		1,674,581
Senior Notes, unamortized deferred financing costs	$ 18,095		$ 13,918

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

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