Stock-based Compensation (Tables)

3 Months Ended

Mar. 31, 2021

Stock-based Compensation

Summary of the stock-based compensation activity

	Quarter ended March 31,
	2021		2020
	(in thousands)
Grants:
Units:
Performance-based restricted share units ("RSUs")		310		422
Stock options		249		273
Time-based RSUs		171		304
Grant date fair value:
Performance-based RSUs	$	18,234	$	14,768
Stock options		5,116		2,770
Time-based RSUs		10,064		10,662
Total	$	33,414	$	28,200
Vestings and exercises:
Performance-based RSUs vested		640		603
Stock options exercised		88		180
Time-based RSUs vested		305		348
Compensation expense	$	10,877	$	12,368