Cash Dividends (Details) (USD $)	0 Months Ended	3 Months Ended
Dec. 02, 2014	Dec. 01, 2014	Sep. 03, 2014	Dec. 31, 2014	Dec. 31, 2013
Cash Dividends
Cash dividends declared, per share (in dollars per share)	$ 0.6875		$ 0.6875	$ 0.6875	$ 0.6250
Cash dividend paid, per share (in dollars per share)		$ 0.6875

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

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 S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration