Subsequent Events (Details) - Class A Common Stock - $ / shares	9 Months Ended
Sep. 30, 2017	Oct. 16, 2017
Subsequent Event [Line Items]
Declaration date of quarterly dividend	Oct. 16, 2017
Dividend payment date	Nov. 13, 2017
Dividend record date	Oct. 31, 2017
Subsequent Event
Subsequent Event [Line Items]
Dividend amount per share (in dollars)		$ 0.24

Date the declared dividend will be paid, in CCYY-MM-DD format.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4304-108586

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- Definition

The per share amount of a dividend declared, but not paid, as of the financial reporting date.

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- Definition

Date the dividend to be paid was declared, in CCYY-MM-DD format.

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- Definition

Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

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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.

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