CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income	$ 150,952	$ 175,459	$ 156,959
Adjustments to reconcile net income to net cash provided by operating activities:
Write-down of impaired assets	42,373
Depreciation and amortization	15,093	16,332	13,834
Amortization of deferred sales commissions	53,863	53,855	58,381
Share-based compensation	49,993	46,473	40,338
Excess tax benefits from share-based payment arrangements	(6,791)	(8,020)	(6,128)
Gain on sale of available for sale investment securities	(3,163)	(2,258)	(2,893)
Net purchases and sales or maturities of trading securities	(27,470)	59,034	(60,623)
Unrealized (gain) loss on trading securities	(5,470)	1,231	(5,101)
Loss on sale and retirement of property and equipment	5,326	2,059	201
Capital gains and dividends reinvested			(365)
Deferred income taxes	(6,236)	2,395	(5,200)
Changes in assets and liabilities:
Cash and cash equivalents - restricted	(42,812)	30,628	(8,256)
Receivables from funds and separate accounts	(2,044)	(4,608)	7,714
Other receivables	(29,422)	(32,260)	94,678
Other assets	2,872	(512)	(4,245)
Deferred sales commissions	(54,430)	(57,933)	(58,968)
Accounts payable and payable to investment companies	65,753	(2,002)	(88,946)
Other liabilities	25,048	3,266	9,263
Net cash provided by operating activities	233,435	283,139	140,643
Cash flows from investing activities:
Purchases of available for sale investment securities	(51,676)	(102,451)	(76,961)
Proceeds from sales and maturities of available for sale investment securities	49,809	92,282	26,463
Additions to property and equipment	(15,300)	(20,078)	(17,313)
Proceeds from sales of property and equipment	38	5	5
Net cash used in investing activities	(17,129)	(30,242)	(67,806)
Cash flows from financing activities:
Debt repayment			(10,000)
Dividends paid	(171,267)	(68,766)	(65,194)
Repurchase of common stock	(48,688)	(65,463)	(65,872)
Exercise of stock options	105	5,080	13,057
Excess tax benefits from share-based payment arrangements	6,791	8,020	6,128
Net cash used in financing activities	(213,059)	(121,129)	(121,881)
Net increase (decrease) in cash and cash equivalents	3,247	131,768	(49,044)
Cash and cash equivalents at beginning of year	327,083	195,315	244,359
Cash and cash equivalents at end of year	330,330	327,083	195,315
Less cash and cash equivalents of discontinued operations at end of year	2,303	3,167	5,245
Cash and cash equivalents of continuing operations at end of year	328,027	323,916	190,070
Cash paid for:
Income taxes (net)	98,181	105,080	92,038
Interest	$ 10,286	$ 10,426	$ 10,920