Derivatives and Hedging (Details) - Outstanding Derivatives Contracts	12 Months Ended
Dec. 31, 2017 USD ($) outstanding_contract	Dec. 31, 2016 USD ($) outstanding_contract
Derivatives, Fair Value [Line Items]
Number of Outstanding Contracts \| outstanding_contract	142	87
Notional Amounts	$ 2,086,764,000	$ 786,946,000
Fair Value Asset (Liability)	3,860,000	(2,669,000)
Unrealized Gain (Loss) Recorded in OCI	2,483,000	$ (1,409,000)
Interest rate swaps
Derivatives, Fair Value [Line Items]
Notional Amounts	$ 1,400,000,000
Other assets \| Interest rate swaps \| Designated as hedging instrument
Derivatives, Fair Value [Line Items]
Number of Outstanding Contracts \| outstanding_contract	5
Notional Amounts	$ 1,400,000,000
Fair Value Asset (Liability)	3,412,000
Unrealized Gain (Loss) Recorded in OCI	$ 2,483,000
Other liabilities \| Interest rate swaps \| Designated as hedging instrument
Derivatives, Fair Value [Line Items]
Number of Outstanding Contracts \| outstanding_contract		3
Notional Amounts		$ 700,000,000
Fair Value Asset (Liability)		(2,349,000)
Unrealized Gain (Loss) Recorded in OCI		$ (1,409,000)
Other current assets \| Foreign currency forwards
Derivatives, Fair Value [Line Items]
Number of Outstanding Contracts \| outstanding_contract	137
Notional Amounts	$ 686,764,000
Fair Value Asset (Liability)	448,000
Unrealized Gain (Loss) Recorded in OCI	$ 0
Accrued liabilities \| Foreign currency forwards
Derivatives, Fair Value [Line Items]
Number of Outstanding Contracts \| outstanding_contract		84
Notional Amounts		$ 86,946,000
Fair Value Asset (Liability)		(320,000)
Unrealized Gain (Loss) Recorded in OCI		$ 0

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

Fair values as of the balance sheet date of the net amount of all assets and liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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- Definition

The effective portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments that was recognized in other comprehensive income during the current period.

+ References

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

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- Definition

The number of derivative instruments of a particular group held by the entity.

+ 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=84234895&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=84234895&loc=SL5579245-113959

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+ References

No definition available.

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