Long-Term Debt (Schedule Of Interest Expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Long-Term Debt [Abstract]
Cash payments for interest	$ 61,873us-gaap_InterestPaid	$ 62,609us-gaap_InterestPaid	$ 56,522us-gaap_InterestPaid
Commitment and other fees paid	2,767bas_CommitmentAndOtherFeesPaid	1,905bas_CommitmentAndOtherFeesPaid	1,658bas_CommitmentAndOtherFeesPaid
Amortization of debt issuance costs and premium on senior secured notes	2,934	2,878	2,646
Change in accrued interest	(269)	129	1,559
Capitalized Interest	(349)us-gaap_InterestCostsCapitalized	(354)us-gaap_InterestCostsCapitalized	(353)us-gaap_InterestCostsCapitalized
Other	86us-gaap_InterestExpenseOther	40us-gaap_InterestExpenseOther	406us-gaap_InterestExpenseOther
Total interest expense	$ 67,042us-gaap_InterestExpense	$ 67,207us-gaap_InterestExpense	$ 62,438us-gaap_InterestExpense

Amortization of debt issuance costs and discount on senior secured notes.

No definition available.

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- Definition

Commitment and other fees paid.

+ References

No definition available.

+ Details

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- Details

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- Definition

The increase (decrease) during the reporting period in interest payable, which represents the amount owed to note holders, bond holders, and other parties for interest earned on loans or credit extended to the reporting entity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

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- Definition

Amount of interest capitalized during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Allowance for Funds Used during Construction

-URI http://asc.fasb.org/extlink&oid=6504829

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

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-Section 50

-Paragraph 1

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- Definition

Amount of the cost of borrowed funds accounted for as interest expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 835

-SubTopic 20

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-Name Accounting Standards Codification

-Topic 942

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-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.9)

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 9

-Article 9

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- Definition

Interest expense on all other items not previously classified. For example, includes dividends associated with redeemable preferred stock of a subsidiary that is treated as a liability in the parent's consolidated balance sheet.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4D

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-Section S99

-Paragraph 1

-Subparagraph -4

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- Definition

The amount of cash paid for interest during the period.

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 50

-Paragraph 2

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