Borrowings - Debt Redemption (Details) - Senior Notes	3 Months Ended
Dec. 31, 2020
6 3/4% Senior Notes Maturing March of 2025
Debt Instrument [Line Items]
Stated interest rate on debt instrument	6.75%
Percentage of principal amount redeemed	35.00%
Redemption price percentage	106.75%
Percentage of principal amount outstanding after redemption	65.00%
6 3/4% Senior Notes Maturing March of 2025 \| Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price percentage	100.00%
6 3/4% Senior Notes Maturing March of 2025 \| Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption price percentage	105.063%
6 3/4% Senior Notes Maturing March of 2025 \| Debt Instrument, Redemption, Period Three
Debt Instrument [Line Items]
Redemption price percentage	103.375%
6 3/4% Senior Notes Maturing March of 2025 \| Debt Instrument, Redemption, Period Four
Debt Instrument [Line Items]
Redemption price percentage	101.688%
6 3/4% Senior Notes Maturing March of 2025 \| Debt Instrument, Redemption, Period Five
Debt Instrument [Line Items]
Redemption price percentage	100.00%
5 7/8% Senior Notes Maturing October 2027
Debt Instrument [Line Items]
Stated interest rate on debt instrument	5.88%
Percentage of principal amount redeemed	35.00%
Redemption price percentage	105.875%
Percentage of principal amount outstanding after redemption	65.00%
5 7/8% Senior Notes Maturing October 2027 \| Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price percentage	100.00%
5 7/8% Senior Notes Maturing October 2027 \| Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption price percentage	102.938%
5 7/8% Senior Notes Maturing October 2027 \| Debt Instrument, Redemption, Period Three
Debt Instrument [Line Items]
Redemption price percentage	101.958%
5 7/8% Senior Notes Maturing October 2027 \| Debt Instrument, Redemption, Period Four
Debt Instrument [Line Items]
Redemption price percentage	100.979%
5 7/8% Senior Notes Maturing October 2027 \| Debt Instrument, Redemption, Period Five
Debt Instrument [Line Items]
Redemption price percentage	100.00%
7 1/4% Senior Notes Maturing October 2029
Debt Instrument [Line Items]
Stated interest rate on debt instrument	7.25%
Percentage of principal amount redeemed	35.00%
Redemption price percentage	107.25%
Percentage of principal amount outstanding after redemption	65.00%
7 1/4% Senior Notes Maturing October 2029 \| Debt Instrument, Redemption, Period One
Debt Instrument [Line Items]
Redemption price percentage	100.00%
7 1/4% Senior Notes Maturing October 2029 \| Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption price percentage	103.625%
7 1/4% Senior Notes Maturing October 2029 \| Debt Instrument, Redemption, Period Three
Debt Instrument [Line Items]
Redemption price percentage	102.417%
7 1/4% Senior Notes Maturing October 2029 \| Debt Instrument, Redemption, Period Four
Debt Instrument [Line Items]
Redemption price percentage	101.208%
7 1/4% Senior Notes Maturing October 2029 \| Debt Instrument, Redemption, Period Five
Debt Instrument [Line Items]
Redemption price percentage	100.00%

Debt Instrument, Redemption Price, Percentage of Principal Amount Outstanding After Redemption

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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- Definition

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.

+ References

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- Definition

Percentage price of original principal amount of debt at which debt can be redeemed by the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph e
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

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- Definition

Percentage of principal amount of debt redeemed.

+ References

No definition available.

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