Fair Value Measurement Level 3 Reconciliation (Details) - Unobservable Inputs (Level 3) - Private Equity Funds - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 2,573	$ 1,772	$ 2,595	$ 1,785
Total unrealized gains included in earnings relating to assets still held at the reporting date	2,934	836	2,912	823
Ending balance	$ 5,507	$ 2,608	$ 5,507	$ 2,608