Subsequent Events (Details) (USD $)		0 Months Ended
Apr. 29, 2014 Dividend Declared Class A common stock	Apr. 29, 2014 Dividend Declared Class B common stock	May 15, 2014 Subsequent event Minimum	May 15, 2014 Subsequent event Maximum
Subsequent events
Quarterly dividend declared (in dollars per share)	$ 0.15	$ 0.15
Term for settlement of liabilities to plan participants under SERP			12 months	24 months

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

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

Name:	us-gaap_DividendsPayableAmountPerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant