Annual report pursuant to Section 13 and 15(d)

Segments - Fee Revenue Classified by Country (Detail)

v3.19.2
Segments - Fee Revenue Classified by Country (Detail) - USD ($)
$ in Thousands
3 Months Ended 12 Months Ended
Apr. 30, 2019
Jan. 31, 2019
Oct. 31, 2018
Jul. 31, 2018
Apr. 30, 2018
Jan. 31, 2018
Oct. 31, 2017
Jul. 31, 2017
Apr. 30, 2019
Apr. 30, 2018
Apr. 30, 2017
Segment Reporting Information [Line Items]                      
Total revenue                 $ 1,973,862 $ 1,819,519 $ 1,621,669
Fee Revenue                      
Segment Reporting Information [Line Items]                      
Total revenue $ 490,756 $ 474,504 $ 495,205 $ 465,568 $ 475,364 $ 447,581 $ 443,018 $ 401,254 1,926,033 1,767,217 1,565,521
Fee Revenue | UNITED STATES                      
Segment Reporting Information [Line Items]                      
Total revenue                 859,969 778,470 728,871
Fee Revenue | United Kingdom                      
Segment Reporting Information [Line Items]                      
Total revenue                 202,055 176,091 145,551
Fee Revenue | Other Countries                      
Segment Reporting Information [Line Items]                      
Total revenue                 $ 864,009 $ 812,656 $ 691,099