Condensed Consolidated Statements of Financial Condition (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Accumulated depreciation (in dollars)	$ 103,418	$ 98,595
Other assets, fair value (in dollars)	$ 6,250	$ 5,984
Treasury stock shares	169,649	169,649
Class A
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock shares authorized	1,000,000,000	1,000,000,000
Common stock shares issued	38,379,858	38,379,858
Common stock shares outstanding	38,210,209	38,210,209
Class B
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock shares authorized	175,000,000	175,000,000
Common stock shares issued	0	0
Common stock shares outstanding	0	0
Class C
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock shares authorized	90,000,000	90,000,000
Common stock shares issued	20,976,598	20,976,598
Common stock shares outstanding	20,922,855	20,976,598
Class D
Common stock, par value (in dollars per share)	$ 0.00001	$ 0.00001
Common stock shares authorized	175,000,000	175,000,000
Common stock shares issued	79,610,490	79,610,490
Common stock shares outstanding	79,610,490	79,610,490