Benefit Plans (Details)		3 Months Ended	12 Months Ended
	Oct. 15, 2018	Mar. 31, 2021 USD ($) quarter installment shares	Mar. 31, 2021 USD ($) quarter installment $ / shares shares	Mar. 31, 2020 USD ($) $ / shares shares	Mar. 31, 2019 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum contribution from employer			50.00%
Employer matching contribution, percent			6.00%
Employer contribution, percent of match			3.00%
Amount of cost recognized			$ 1,600,000	$ 1,600,000	$ 1,500,000
Annual salary increase used for estimating unfunded liability		3.50%
Discount rate used for estimating unfunded liability		6.00%	6.00%
Retirement age used for estimating unfunded liability		65
Stock Option Plans
Number of shares available for grant (in shares) | shares		170,377	170,377
Percentage of shares subject to performance shares			100.00%
Weighted-average fair value at the grant date | $ / shares			$ 58.48	$ 57.69	$ 53.50
Restricted Stock
Granted during the period (in dollars per share) | $ / shares					$ 101.61
Schedule of vesting of restricted shares on basis of compounded annual EPS growth [Abstract]
Stock-based compensation			$ 19,281,278	$ 28,952,161	$ 17,635,309
Stock Options Plans
Stock Option Plans
Shares of authorized common stock reserved for issuance (in shares) | shares		3,350,000	3,350,000
Compensation Cost Not yet Recognized
Total unrecognized stock-based compensation expense related to non-vested stock options		$ 8,400,000	$ 8,400,000
Weighted average period for recognition			3 years 8 months 12 days
Schedule of vesting of restricted shares on basis of compounded annual EPS growth [Abstract]
Weighted average period for recognition			3 years 8 months 12 days
Stock-based compensation			$ 3,804,674	$ 5,522,883	$ 3,991,967
Restricted Stock
Stock Option Plans
Number of installments | installment		6	6
Restricted Stock
Granted during the period (in shares) | shares			52,735	11,223	760,420
Granted during the period (in dollars per share) | $ / shares			$ 106.28	$ 90.23
Schedule of vesting of restricted shares on basis of compounded annual EPS growth [Abstract]
Stock-based compensation			$ 15,476,603	$ 23,429,277	$ 13,643,343
Unrecognized compensation cost related to unvested restricted stock		$ 27,200,000	27,200,000
Equity Classified Awards
Schedule of vesting of restricted shares on basis of compounded annual EPS growth [Abstract]
Stock-based compensation			$ 19,281,277	28,952,160	17,635,310
Performance Shares
Stock Option Plans
Vesting period	10 years
Number of consecutive quarters | quarter		4	4
Compensation Cost Not yet Recognized
Weighted average period for recognition			2 years 6 months
Schedule of vesting of restricted shares on basis of compounded annual EPS growth [Abstract]
Weighted average period for recognition			2 years 6 months
Service Options
Stock Option Plans
Vesting period			10 years
Number of installments | installment		6	6
Maximum | Stock Options Plans
Stock Option Plans
Expiration period			10 years
Vesting period			6 years
Supplemental Employee Retirement Plans, Defined Benefit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Pension and other postretirement benefits cost (reversal of cost)			$ 550,000	580,000	$ 650,000
Unfunded liability		$ 6,400,000	$ 6,400,000	$ 6,800,000