Stock Option Summary (Details) - Share-based Payment Arrangement, Option [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
[Line Items]
Outstanding, beginning balance (in shares)	433	458	433	458
Outstanding, beginning balance, weighted average exercise price per share (in dollars per share)	$ 61.95	$ 56.38	$ 61.95	$ 56.38
Outstanding, weighted average remaining contractual life	6 years 10 months 24 days	7 years	6 years 4 months 24 days	7 years 3 months 18 days
Outstanding, beginning balance, aggregate intrinsic value	$ 14,697	$ 12,641	$ 14,697	$ 12,641
Granted (in shares)			0	73
Granted, weighted average exercise price (in dollars per share)				$ 87.27
Granted, weighted average grant date fair value			$ 0	$ 26.72
Exercised (in shares)			(31)	(47)
Exercised, weighted average exercise price (in dollars per share)			$ 66.97	$ 51.52
Exercised, aggregate intrinsic value			$ 1,121	$ 1,131
Forfeited (in share)			(6)
Forfeited, weighted average grant date fair value (in dollars per share)			$ 83.33
Outstanding, ending balance (in shares)			396	484
Outstanding, ending balance, weighted average exercise price per share (in dollars per share)			$ 61.25	$ 61.48
Outstanding, weighted average remaining contractual life	6 years 10 months 24 days	7 years	6 years 4 months 24 days	7 years 3 months 18 days
Outstanding, ending balance, aggregate intrinsic value			$ 15,349	$ 4,871
Exercisable (in shares)			288
Exercisable, weighted average exercise price (in dollars per share)			$ 54.75
Exercisable, weighted average remaining contractual term			5 years 7 months 6 days
Exercisable, aggregate intrinsic value			$ 13,048