Investment in joint venture.

No definition available.

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- Definition

Line of Credit Maturity Month and Year

+ References

No definition available.

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- Definition

Subsequent Events [Line Items]

+ References

No definition available.

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

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- Definition

Amount of the required periodic payments including both interest and principal payments.

+ References

Reference 1: 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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

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- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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- Definition

Percentage of an entity's outstanding debt that is designated as a hedged item in cash flow, fair value, or net investment hedge.

+ References

No definition available.

+ Details

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Subsequent Events - Additional Information (Detail) ر.س in Billions			1 Months Ended		12 Months Ended
	Oct. 26, 2018 USD ($)	Oct. 26, 2018 SAR (ر.س)	Sep. 30, 2018 USD ($)	Mar. 31, 2014	Aug. 31, 2018 USD ($)
Subsequent Events [Line Items]
Swap agreement interest rate				50.00%
Fixed interest rate				3.74%
Term Loan
Subsequent Events [Line Items]
Senior term debt					$ 200,000,000
Subsequent Event
Subsequent Events [Line Items]
Periodic payment			$ 1,970,000
Swap agreement interest rate			50.00%
Fixed interest rate			2.99%
Subsequent Event \| Saudi Railway Company
Subsequent Events [Line Items]
Investment in joint venture	$ 270,000,000	ر.س 1
Subsequent Event \| Term Loan
Subsequent Events [Line Items]
Senior term debt			$ 170,000,000
Subsequent Event \| New Five Year Term Loan
Subsequent Events [Line Items]
Senior term debt			$ 225,000,000
LIBOR
Subsequent Events [Line Items]
Debt instrument, percentage points added to the reference rate				1.75%
LIBOR \| Subsequent Event
Subsequent Events [Line Items]
Debt instrument, percentage points added to the reference rate			1.50%
Prime Rate \| Subsequent Event
Subsequent Events [Line Items]
Debt instrument, percentage points added to the reference rate			0.50%
Revolving Line of Credit, 1st Component of Senior Secured Credit Facilities
Subsequent Events [Line Items]
Line of credit facility maximum capacity					$ 550,000,000
Line of credit maturity date					2020-10
Revolving Line of Credit, 1st Component of Senior Secured Credit Facilities \| Subsequent Event
Subsequent Events [Line Items]
Line of credit facility maximum capacity			$ 600,000,000
Line of credit maturity date			2023-09
Revolving Line of Credit, 1st Component of Senior Secured Credit Facilities \| LIBOR
Subsequent Events [Line Items]
Debt instrument, percentage points added to the reference rate					1.75%
Revolving Line of Credit, 1st Component of Senior Secured Credit Facilities \| LIBOR \| Subsequent Event
Subsequent Events [Line Items]
Debt instrument, percentage points added to the reference rate			1.50%
Revolving Line of Credit, 1st Component of Senior Secured Credit Facilities \| Prime Rate
Subsequent Events [Line Items]
Debt instrument, percentage points added to the reference rate					0.75%
Revolving Line of Credit, 1st Component of Senior Secured Credit Facilities \| Prime Rate \| Subsequent Event
Subsequent Events [Line Items]
Debt instrument, percentage points added to the reference rate			0.50%