Derivatives And Risk Management (Interest Rate Swap Agreements) (Details) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($) Caontracts	Dec. 31, 2018 USD ($) Caontracts
Derivatives, Fair Value [Line Items]
Secured Debt	$ 1,979,200	$ 1,889,200
Derivative, Fair Value, Amount Offset Against Collateral, Net	10,148	51,747
Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Amount Offset Against Collateral, Net	$ 6,770	$ 530
2019 \| Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Number of contracts \| Caontracts		6
Derivative, Notional Amount		$ 70,000
Derivative, Maturity Date		2019
2020 \| Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Number of contracts \| Caontracts	7	6
Derivative, Notional Amount	$ 70,000	$ 60,000
Derivative, Maturity Date	2020	2020
2021 \| Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Number of contracts \| Caontracts	3	2
Derivative, Notional Amount	$ 35,000	$ 25,000
Derivative, Maturity Date	2021	2021
2022 \| Interest Rate Swap Agreements [Member]
Derivatives, Fair Value [Line Items]
Number of contracts \| Caontracts	10	7
Derivative, Notional Amount	$ 110,000	$ 80,000
Derivative, Maturity Date	2022	2022

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

Description of the relevant terms of the derivative. Includes the type of instrument, risk being hedged, notional amount, counterparty, inception date, maturity date, relevant interest rates, strike price, cap price, and floor price.

+ References

No definition available.

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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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=d3e41678-113959

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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

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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5579245-113959

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=109980867&loc=SL5580258-113959

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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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
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-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: 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))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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