Derivatives And Risk Management (Interest Rate Swap Agreements) (Details) (USD $)	12 Months Ended
Dec. 31, 2014 Caontracts	Dec. 31, 2013 Caontracts
Derivatives, Fair Value [Line Items]
Secured Debt	$ 1,511,700,000us-gaap_SecuredDebt	$ 1,376,700,000us-gaap_SecuredDebt
Derivative, Fair Value, Amount Offset Against Collateral, Net	44,390,000	8,732,000
2013 \| Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Number of contracts		2
Derivative, Notional Amount		50,000,000
Derivative, Maturity Date		Dec. 31, 2014
2015 \| Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Number of contracts	5	2
Derivative, Notional Amount	75,000,000	45,000,000
Derivative, Maturity Date	Dec. 31, 2015	Dec. 31, 2015
2016 \| Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Number of contracts	5	2
Derivative, Notional Amount	95,000,000	40,000,000
Derivative, Maturity Date	Dec. 31, 2016	Dec. 31, 2016
2017 \| Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Number of contracts	3	1
Derivative, Notional Amount	45,000,000	15,000,000
Derivative, Maturity Date	Dec. 31, 2017	Dec. 31, 2017
2018 \| Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Number of contracts	9	4
Derivative, Notional Amount	$ 205,000,000	$ 95,000,000
Derivative, Maturity Date	Dec. 31, 2018	Dec. 31, 2018

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Article 12

-Section 13

-Sentence Column B

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- Definition

The net amount as of the balance sheet date of the fair value of derivative assets and derivative liabilities that in accordance with the entity's accounting policy were offset against collateral under a master netting arrangement.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 8

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=d3e41678-113959

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- Definition

Date the derivative contract matures, in CCYY-MM-DD format.

+ References

No definition available.

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- Definition

Number of interest rate derivative instruments held by the entity at the reporting date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5579245-113959

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- Definition

Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.16)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 20, 22

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.16)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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