Stockholders' Equity (Details) (USD $)	0 Months Ended	3 Months Ended	9 Months Ended
Nov. 05, 2013	Aug. 07, 2013	May 07, 2013	Feb. 13, 2013	Sep. 30, 2013	Sep. 30, 2013 2012 Repurchase Program [Member]
Class of Stock [Line Items]
Maximum number of shares authorized to be repurchased						5,000,000
Stock Repurchased					43,435	0
Dividend amount to be paid, per common share	$ 0.255	$ 0.2475	$ 0.2400	$ 0.2325
Dividend, declaration date	Nov. 05, 2013	Aug. 07, 2013	May 07, 2013	Feb. 12, 2013
Dividend, date to be paid	Dec. 04, 2013	Sep. 03, 2013	Jun. 04, 2013	Mar. 04, 2013
Dividend, date of record	Nov. 18, 2013	Aug. 19, 2013	May 20, 2013	Feb. 25, 2013

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

+ References

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

+ Details

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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=6367179&loc=d3e4304-108586

+ Details

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- Definition

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

+ References

+ Details

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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.

+ Details

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- Definition

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

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

+ Details

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- Definition

The number of shares authorized to be repurchased by an entity's Board of Directors under a stock repurchase plan.

+ References

No definition available.

+ Details

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