Debt - Convertible Senior Notes (Details)	1 Months Ended		2 Months Ended	3 Months Ended	9 Months Ended
	Oct. 31, 2021 USD ($)	Sep. 30, 2021 USD ($) D $ / shares shares	Oct. 31, 2021 USD ($)	Sep. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2021 USD ($) $ / shares shares	Sep. 30, 2020 USD ($)	Sep. 16, 2021 $ / shares	Sep. 15, 2021 $ / shares
Debt
Repayment of debt					$ 42,965,000	$ 42,858,000
Conversion price (per share) | $ / shares							$ 37.74	$ 25
Convertible senior notes, due 2026
Debt
Principal Amount of debt		$ 425,000,000		$ 425,000,000	$ 425,000,000
Interest rate (stated)		0.75%		0.75%	0.75%
Issue price ( as percentage)		100.00%		100.00%	100.00%
Net proceeds					$ 413,500,000
Sale price (as percentage)		130.00%
Consecutive trading days | D		30
Threshold trading days | D		20
Redemption price (as percentage)		100.00%
Principal amount denomination for conversion		$ 1,000
Conversion ratio		0.0399956
Conversion price (per share) | $ / shares		$ 25.0027		$ 25.0027	$ 25.0027
Business days | D		5
Capped calls, authorized shares | shares		5,736,869		5,736,869	5,736,869
Consecutive trading period | D		5
Trading price per $1,000notes (as percentage)		98.00%		98.00%	98.00%
Conditional conversion ratio		0.0529941
Interest expense				$ 200,000	$ 200,000
Calculated interest rate		1.30%		1.30%	1.30%
Initial strike price | $ / shares					$ 25.0027
Initial cap price | $ / shares					$ 37.7400
Amount paid for capped calls	$ 10,600,000	$ 42,300,000	$ 52,900,000
Notes Issued On Exercise Of Initial Purchasers' Option [Member]
Debt
Principal Amount of debt		$ 40,000,000		$ 40,000,000	$ 40,000,000