Investments (Tables)

12 Months Ended

Dec. 31, 2017

Investments, Debt and Equity Securities [Abstract]

Summary of Investments

Investments consist of:

	December 31,
	2017		2016
	(in thousands)
Trading:
U.S. Treasury Bills	$	52,609	$	28,937
Long-term incentive compensation-related	51,758		50,935
Seed capital	160,573		188,053
Equities	81,154		6,602
Exchange-traded options	4,981		3,106
Investments in limited partnership hedge funds:
Long-term incentive compensation-related	14,276		16,826
Seed capital	22,923		23,704
Private equity (seed capital)	38,186		45,278
Time deposits	5,138		70,097
Other (including available-for-sale investments)	11,991		7,567
Total investments	$	443,589	$	441,105

Summary of the Cost and Fair Value of Available-For-Sale and Trading Investments

The portion of trading gains (losses) related to trading securities held as of December 31, 2017 and 2016 were as follows:

	December 31,
	2017		2016
	(in thousands)
Net gains recognized during the period	$	15,589	$	7,030
Less: net gains (losses) recognized during the period on trading securities sold during the period	14,118		(11,294		)
Unrealized gains recognized during the period on trading securities held	$	1,471	$	18,324