Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Revenues:
Investment management fees	$ 185,914	$ 193,624	$ 368,019	$ 381,661
Underwriting and distribution fees	171,508	169,001	338,486	334,268
Shareholder service fees	36,568	38,009	72,943	75,121
Total	393,990	400,634	779,448	791,050
Operating expenses:
Underwriting and distribution	195,762	195,608	391,182	390,559
Compensation and related costs (including share-based compensation of $11,333, $14,593, $23,806 and $27,679, respectively)	52,829	48,589	106,324	98,598
General and administrative	27,897	27,183	53,575	50,939
Subadvisory fees	2,394	2,069	4,781	3,946
Depreciation	4,064	3,541	8,098	6,790
Total	282,946	276,990	563,960	550,832
Operating income	111,044	123,644	215,488	240,218
Investment and other income	9	6,100	3,981	10,000
Interest expense	(2,765)	(2,755)	(5,531)	(5,510)
Income before provision for income taxes	108,288	126,989	213,938	244,708
Provision for income taxes	40,843	44,001	79,380	86,856
Net income	$ 67,445	$ 82,988	$ 134,558	$ 157,852
Net income per share, basic and diluted:
Net income per share, basic and diluted (in dollars per share)	$ 0.80	$ 0.98	$ 1.61	$ 1.86
Weighted average shares outstanding, basic and diluted:
Weighted average shares outstanding, basic and diluted (in shares)	84,079	85,073	83,831	85,046