Subsequent events.

No definition available.

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- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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- Definition

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

+ References

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=98513485&loc=d3e4304-108586

+ Details

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- Definition

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

+ References

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- Definition

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

+ References

No definition available.

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Subsequent Events - Additional Information (Narrative) (Details) - Subsequent Event [Member] - $ / shares	May 25, 2018	May 11, 2018	Apr. 27, 2018
Subsequent Events [Line Items]
Date of announcement of dividend			Apr. 27, 2018
Date of payment of dividend	May 25, 2018
Date of record of dividend		May 11, 2018
Class A Stock
Subsequent Events [Line Items]
Quarterly dividend payable amount per share			$ 0.11
Class B Stock
Subsequent Events [Line Items]
Quarterly dividend payable amount per share			$ 0.11