Fair Value Measurements (Unobervable Quantitative Input Ratios) (Details) - Recurring - Level 3 - Real estate fund investments	12 Months Ended
Dec. 31, 2016
Minimum
Unobservable Quantitative Input
Discount rates	10.00%
Capitalization rate	4.30%
Maximum
Unobservable Quantitative Input
Discount rates	14.90%
Capitalization rate	5.80%
Weighted Average
Unobservable Quantitative Input
Discount rates	12.60%
Capitalization rate	5.30%

Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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Period Type:	duration