Fair Value Measurements (Narratives) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($) Investments	Dec. 31, 2015 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Real estate fund investments	$ 524,150	$ 574,761
Real Estate Fund [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number Of Investments Held By Fund | Investments	6
Real estate fund investments	$ 524,150
Excess of fair value over cost	$ 215,215
Real Estate Fund [Member] | Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Anticipated Investment Holding Period	1 year
Real Estate Fund [Member] | Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Measurement Anticipated Investment Holding Period	4 years 6 months