Other Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 13, 2021	Sep. 30, 2021
Accrued expenses and other current liabilities
Accrued salaries and benefits	$ 643,100			$ 661,800
Accrued contract costs	1,254,300			1,202,100
Other accrued expenses	365,700			310,300
Total accrued expenses	2,263,126			2,174,201
Restructuring costs	3,371	$ 13,038
Accrued restructuring expenses	300	1,700
Dividend paid per share in cash			$ 0.15
Accrued and unpaid dividend	21,500
Personnel and other costs
Accrued expenses and other current liabilities
Restructuring costs	2,200	10,200
Real estate costs
Accrued expenses and other current liabilities
Restructuring costs	1,200	$ 2,800
Professional liability accrual
Accrued expenses and other current liabilities
Accrued contract costs	$ 744,000			$ 736,400