Subsequent Events (Details) (USD $)	3 Months Ended	6 Months Ended	0 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jul. 03, 2013 Subsequent Event [Member]	Jul. 09, 2013 Nonvoting Common Stock [Member] Subsequent Event [Member]	Jul. 09, 2013 Common Shares Repurchased And Constructively Retired [Member] Subsequent Event [Member]
Subsequent Event [Line Items]
Dividends paid per common share	$ 0.000	$ 0.375	$ 0.375	$ 0.750	$ 0.50
Shares cancelled, shares			940,445			29,240	1,538,686

Number of shares of common and preferred stock retired from treasury during the period.

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

-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 12

-Paragraph 10

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 3: 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

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