Related Party Transactions (Details) (Class A Common Stock, USD $)	0 Months Ended	9 Months Ended
May 02, 2014	Sep. 30, 2014
Related Party Transaction [Line Items]
Stock Repurchased and Retired During Period, Shares		362,121
Director [Member]
Related Party Transaction [Line Items]
Stock Repurchased and Retired During Period, Shares		29,615
Stock Repurchased and Retired During Period, Weighted Average Price	$ 25.01

Number of shares that have been repurchased and retired during the period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section 50

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 29, 30

-Article 5

Name:	us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration