Carried Interest Due from Investment Funds (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Activity in the carried interest
Carried Interest recognized during the quarter	$ (365)	$ (1,040)	$ 980
Investment Funds
Activity in the carried interest
Balance at beginning of year	8,552	70,906	69,926
Carried Interest recognized during the quarter	(365)	(1,040)	980
Cash received during the quarter	$ (8,187)	(61,314)
Balance at end of year		$ 8,552	$ 70,906