Annual report pursuant to Section 13 and 15(d)

Income taxes - Reconciliation of Tax Provision Using the Federal Statutory Income Tax Rate to Reported Provision (Details)

v3.20.2
Income taxes - Reconciliation of Tax Provision Using the Federal Statutory Income Tax Rate to Reported Provision (Details) - USD ($)
$ in Thousands
12 Months Ended
Sep. 30, 2020
Sep. 30, 2019
Sep. 30, 2018
Reconciliation of actual provision for income taxes and provision for income taxes resulting from the use of federal statutory income tax      
Federal income tax provision at statutory rate of 21%, 21% and 24.5%, respectively $ 60,284 $ 66,637 $ 73,396
State income taxes, net of federal benefit 17,480 14,825 12,348
Foreign taxation (463) 1,210 (1,531)
Permanent items 2,200 2,682 1,176
Tax credits (4,149) (3,730) (2,438)
Toll tax 0 (481) 9,425
Deferred tax liability - tax rate change 0 0 (10,514)
Vesting of equity compensation (2,038) (4,783) (2,849)
Other (761) 465 (620)
Provision for income taxes $ 72,553 $ 76,825 $ 78,393
Statutory income tax rate (as a percent) 21.00% 21.00% 24.50%