Fair Value Of Financial Instruments (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Commitments Investments In Affiliated And Unaffiliated Partnerships	$ 11,300	$ 11,300	$ 11,500
General and limited partnership interests in investment partnerships	51,200	51,200	42,100
Direct investments in private equity companies held by private equity funds	18,100	18,100	$ 21,200
Fair Value Level One To Level Two Transfers Amount	2,400	5,400
Transfers, Out of Level 3, Assets	$ 0	$ 5,900
Stated interest rate	5.375%	5.375%
Maturity date		Dec. 31, 2022
Corporate Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers, Into Level 3	$ 2,877	$ 2,877