Convertible Senior Notes - Conversion (Details) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended
	May 18, 2020	May 31, 2020	Mar. 31, 2021	Mar. 31, 2020	May 29, 2020
Convertible Senior Notes
Net proceeds			$ 10,661	$ 9,024
3.75% Convertible Senior Notes
Convertible Senior Notes
Principal amount	$ 200,000	$ 212,463	$ 197,278		$ 12,500
Less initial purchasers' discount	(6,400)	(6,374)
Less cost of related capped calls		(16,253)
Less other issuance costs	$ (600)	(617)
Net proceeds		$ 189,219