Condensed Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Allowance for doubtful accounts receivables	$ 43,258	$ 40,164
Property, accumulated amortization and depreciation	342,868	339,770
Other intangible assets, accumulated amortization	$ 66,428	$ 65,949
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	15,000,000	15,000,000
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 held by subsidiaries, shares	17,846,122	17,574,805
Series A Preferred Stock [Member]
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Series B Preferred Stock [Member]
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0