Benefit Plans - Valuation Assumptions (Details) - LTIP Unit Awards	12 Months Ended
Dec. 31, 2015	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected dividend yield	1.99%	2.22%
Expected volatility - weighted average	21.34%	30.61%
Expected term	3 years
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility - range used	20.43%	24.28%
Risk-free interest rate	0.10%	0.03%
Expected term		1 year
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility - range used	21.99%	34.66%
Risk-free interest rate	1.16%	0.71%
Expected term		2 years 6 months

Expected dividends to be paid to holders of the underlying shares or financial instruments (expressed as a percentage of the share or instrument's price).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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Period the instrument, asset or liability is expected to be outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Measure of dispersion, in percentage terms (for instance, the standard deviation or variance), for a given stock price.

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Risk-free interest rate assumption used in valuing an instrument.

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Weighted average expected volatility of stock price.

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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.

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No definition available.

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