Subsequent Events - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	9 Months Ended
Sep. 30, 2018	Oct. 18, 2018
Sharyland Holdings, LP
Subsequent Event [Line Items]
Equity interest percentage	50.00%
Noncontrolling Interest, Ownership Percentage by Parent	100.00%
Hunt Consolidated, Inc.
Subsequent Event [Line Items]
Termination fee for termination agreement	$ 40.5
Oncor Electric Delivery Company LLC \| Definitive Agreement
Subsequent Event [Line Items]
Business combination, assumption of net debt	$ 940.0
Subsequent Event \| Oncor Electric Delivery Company LLC \| Definitive Agreement
Subsequent Event [Line Items]
Business acquisition, share price		$ 21.00
Business acquisition, value in cash		$ 1,275.0

Termination fee for termination of agreement.

No definition available.

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- Definition

Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

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- Definition

Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

+ References

No definition available.

+ Details

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- Definition

Amount of long-term debt due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=84161108&loc=d3e4845-128472

+ Details

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- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

+ Details

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- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

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- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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- Details

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- Details

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