Selected Quarterly Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Selected Quarterly Information (Unaudited)
Total revenues	$ 272,230	$ 295,118	$ 295,338	$ 297,615	$ 294,476	$ 289,447	$ 286,657	$ 286,564
Net income attributable to Waddell & Reed Financial, Inc.	$ 46,468	$ 46,305	$ 44,478	$ 46,337	$ 29,765	$ 53,582	$ 24,061	$ 33,871	$ 183,588	$ 141,279	$ 156,695
Net income per share, basic and diluted	$ 0.60	$ 0.58	$ 0.55	$ 0.56	$ 0.36	$ 0.64	$ 0.29	$ 0.40	$ 2.28	$ 1.69	$ 1.90