Condensed Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Allowance for doubtful accounts receivables	$ 20,327	$ 23,540
Property, accumulated amortization and depreciation	261,856	256,286
Goodwill and other intangible assets, accumulated amortization	$ 55,141	$ 51,754
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	15,000,000	15,000,000
Series A Preferred Stock [Member]
Preferred stock, shares issued	7,921	7,921
Preferred stock, shares outstanding	7,921	7,921
Series B Preferred Stock [Member]
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Class A Common Stock [Member]
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	129,766,091	129,766,091
Common stock, shares outstanding	129,766,091	129,766,091
Common stock held by subsidiaries, shares	4,264,125	7,450,745