Investment in AllianceBernstein (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Investment in AllianceBernstein [Abstract]
Investment in AllianceBernstein, beginning of period			$ 1,533,654
Equity in net income attributable to AllianceBernstein Unitholders	48,467	45,440	89,838	88,437
Changes in accumulated other comprehensive income (loss)	1,173	(3,187)	1,710	(6,906)
Additional investments with proceeds from exercises of compensatory options to buy Holding Units, net			12,026	13,281
Cash distributions received from AllianceBernstein			(105,860)	(83,463)
Capital contributions from AllianceBernstein			(855)	0
AllianceBernstein Holding Units retired			(2,355)
AllianceBernstein Holding Units issued to fund long-term incentive compensation plans			4,588
Change in Holding Units held by AllianceBernstein for long-term incentive compensation plans			2,396
Investment in AllianceBernstein, end of period	$ 1,535,142		$ 1,535,142