Debt (Narrative) (Details) $ in Millions	12 Months Ended
Dec. 31, 2020 USD ($)
Debt Instrument [Line Items]
Unrestricted cash borrowing base, maximum	$ 75.0
Credit facility, borrowing base	95.0
Liquidity position, cash	242.0
Liquidity position, cash held by non-guarantors	72.0
Possible increase in credit	170.0
Credit facility, availability	$ 20.0
Fronting fee, percent	0.25%
Unused amount fee, percentage	0.50%
Fixed charge coverage ratio	1.0
Percentage of aggregate commitments	15.00%
London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Basis spread	3.00%
London Interbank Offered Rate (LIBOR) [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Basis spread	3.50%
Base Rate [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Basis spread	2.00%
Base Rate [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Basis spread	2.50%
Letter of Credit [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Basis spread	3.00%
Letter of Credit [Member] \| London Interbank Offered Rate (LIBOR) [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Basis spread	3.50%
Unsecured Senior Notes Due 2024 [Member]
Debt Instrument [Line Items]
Stated interest rate on unsecured senior notes	7.75%
DIP Credit Facility [Member]
Debt Instrument [Line Items]
Credit facility, borrowing capacity	$ 120.0
Letters of Credit Outstanding, Amount	$ 46.6
7.125% Senior Notes [Member]
Debt Instrument [Line Items]
Stated interest rate on unsecured senior notes	7.125%

Credit Facility Agreement, Liquidity Position, Cash

No definition available.

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Namespace Prefix:	cik0000886835_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Credit Facility Agreement, Liquidity Position, Cash held by Non-guarantors

+ References

No definition available.

+ Details

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Namespace Prefix:	cik0000886835_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Credity Facility, Contingent Increase In Borrowing Capacity

+ References

No definition available.

+ Details

Name:	cik0000886835_CredityFacilityContingentIncreaseInBorrowingCapacity
Namespace Prefix:	cik0000886835_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Debt Instrument, Fixed Charge Coverage Ratio

+ References

No definition available.

+ Details

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Namespace Prefix:	cik0000886835_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Fronting Fee, Percentage Rate

+ References

No definition available.

+ Details

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Namespace Prefix:	cik0000886835_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Percent of Aggregate Commitments

+ References

No definition available.

+ Details

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Namespace Prefix:	cik0000886835_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Unused Borrowing Capacity, Percentage Rate

+ References

No definition available.

+ Details

Name:	cik0000886835_DebtInstrumentUnusedBorrowingCapacityPercentageRate
Namespace Prefix:	cik0000886835_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Unrestricted cash borrowing base, maximum.

+ References

No definition available.

+ Details

Name:	cik0000886835_UnrestrictedCashBorrowingBaseMaximum
Namespace Prefix:	cik0000886835_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- 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

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- 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

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ 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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ 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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ 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 210.5-02.19(b),22(b))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

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Namespace Prefix:
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Balance Type:
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- Details

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- Details

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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
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- Details

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Namespace Prefix:
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- Details

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- Details

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