Derivative Financial Instruments Effect of Cash Flow Derivatives on the Balance Sheet and Income Statement, Before Tax (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest Rate Swap Contracts [Abstract]
Loss Reclassified from AOCI into Income (Effective Portion)	$ (916)	$ (1,322)	$ (1,639)
Interest Rate Swap [Member]
Interest Rate Swap Contracts [Abstract]
Amount of Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	768	(1,163)	367
Interest Rate Swap [Member] \| Interest Expense [Member]
Interest Rate Swap Contracts [Abstract]
Loss Reclassified from AOCI into Income (Effective Portion)	(706)	(1,296)	(1,639)
Loss Recognized in Income on Derivative (Ineffective Portion)	0	0	0
Interest Rate Cap [Member]
Interest Rate Swap Contracts [Abstract]
Amount of Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	(183)	(605)	(244)
Interest Rate Cap [Member] \| Interest Expense [Member]
Interest Rate Swap Contracts [Abstract]
Loss Reclassified from AOCI into Income (Effective Portion)	(210)	(27)	0
Loss Recognized in Income on Derivative (Ineffective Portion)	$ 0	$ (1)	$ 0

The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-Subparagraph (a)(1),(2)
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

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- References

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- Definition

Amount before tax of reclassification adjustment from accumulated other comprehensive income of accumulated gain (loss) realized from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's deferred hedging gain (loss).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph c
-URI http://asc.fasb.org/extlink&oid=84234895&loc=d3e41638-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e689-108580

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e637-108580

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- Definition

Amount of unrealized gain (loss) related to the increase or decrease in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective.

+ References

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