XML 95 R79.htm IDEA: XBRL DOCUMENT v3.8.0.1
Quarterly Financial Data (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2017
Sep. 30, 2017
Jun. 30, 2017
Mar. 31, 2017
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Quarterly Financial Data [Abstract]                      
Revenues $ 408,219 $ 386,018 $ 372,331 $ 359,984 $ 368,810 $ 354,641 $ 343,831 $ 334,263 $ 1,526,552 $ 1,401,545 $ 1,334,208
Income before income taxes 152,452 140,769 135,158 128,660 133,053 130,890 124,904 119,638 $ 557,039 $ 508,485 $ 500,480
Net income $ 122,144 $ 101,739 $ 91,769 $ 88,737 $ 88,611 $ 86,704 $ 81,005 $ 77,497      
Basic earnings per common share $ 0.78 $ 0.64 $ 0.58 $ 0.56 $ 0.55 $ 0.54 $ 0.50 $ 0.48 $ 2.56 $ 2.07 $ 2.00
Diluted earnings per common share $ 0.75 $ 0.63 $ 0.57 $ 0.55 $ 0.55 $ 0.53 $ 0.49 $ 0.47 $ 2.49 $ 2.03 $ 1.96
Effective income tax rate 19.90% 27.70% 32.10% 31.00% 33.40% 33.80% 35.20% 35.20% 27.40% 34.30% 33.70%
Net tax benefit from enactment of the Tax Act $ 12,410                    
Net tax benefit from enactment of the Tax Act, per diluted share $ 0.08                    
Extraordinary Item [Member]                      
Extraordinary Item [Line Items]                      
Performance fee associated with SEI-sponsored investment product         $ 12,286            
Sub-advisory expense associated with SEI-sponsored investment product         6,143            
Profit from extraordinary item, net of tax         $ 4,091            
Profit from extraordinary item, net of tax, per diluted share         $ 0.03