Investment in AllianceBernstein (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Investment in AllianceBernstein [Abstract]
Investment in AllianceBernstein, beginning of period			$ 1,533,654
Equity in net income attributable to AllianceBernstein Unitholders	49,876	34,504	139,714	122,941
Changes in accumulated other comprehensive loss	(5,632)	5,233	(3,922)	(1,673)
Additional investments with proceeds from exercises of compensatory options to buy Holding Units, net			12,849	13,859
Cash distributions received from AllianceBernstein			(154,454)	(123,996)
Capital contributions from AllianceBernstein			(1,411)	0
AllianceBernstein Holding Units retired			(4,625)
AllianceBernstein Holding Units issued to fund long-term incentive compensation plans			14,667
Change in Holding Units held by AllianceBernstein for long-term incentive compensation plans			(48)
Investment in AllianceBernstein, end of period	$ 1,536,424		$ 1,536,424