Stockholders' Equity Dividends Declared (Details) - $ / shares	Aug. 02, 2016	May 05, 2016	Feb. 10, 2016	Nov. 03, 2015	Aug. 03, 2015	May 06, 2015	Feb. 10, 2015
Dividends Payable [Line Items]
Dividend, declaration date	Aug. 02, 2016	May 05, 2016	Feb. 10, 2016	Nov. 03, 2015	Aug. 03, 2015	May 06, 2015	Feb. 10, 2015
Dividend amount to be paid, per common share	$ 0.3450	$ 0.3350	$ 0.3250	$ 0.3150	$ 0.3075	$ 0.3000	$ 0.2925
Dividend, date of record	Aug. 17, 2016	May 18, 2016	Feb. 23, 2016	Nov. 17, 2015	Aug. 17, 2015	May 19, 2015	Feb. 23, 2015
Dividend, date to be paid	Sep. 01, 2016	Jun. 02, 2016	Mar. 10, 2016	Dec. 03, 2015	Sep. 01, 2015	Jun. 03, 2015	Mar. 09, 2015

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

Reference 1: 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

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

- 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

Name:	us-gaap_DividendPayableDateToBePaidDayMonthAndYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

+ Details

Name:	us-gaap_DividendsPayableDateDeclaredDayMonthAndYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

+ References

No definition available.

+ Details

Name:	us-gaap_DividendsPayableDateOfRecordDayMonthAndYear
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DividendsPayableLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration