Equity Awards - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Number of shares
Grants (in shares)	0	0	0
Weighted- average exercise price
Grants, weighted-average exercise price (in dollars share)	$ 0	$ 0	$ 0
Stock options
Number of shares
Beginning balance (in shares)	25,574	46,096	256,246
Exercise of stock options, net (in shares)	(1,632)	(20,522)	(208,114)
Forfeitures/expirations (in shares)	(266)	0	(2,036)
Ending balance (in shares)	23,676	25,574	46,096	256,246
Exercisable (in shares)	23,676
Weighted- average exercise price
Beginning Balance, weighted-average exercise price (in dollars share)	$ 65.80	$ 63.49	$ 66.80
Exercises, weighted-average exercise price (in dollars share)	69.44	60.62	67.61
Forfeitures/Expirations, weighted-average exercise price (in dollars share)	87.66	0	58.38
Ending Balance, weighted-average exercise price (in dollars share)	65.30	$ 65.80	$ 63.49	$ 66.80
Weighted-average exercise price (in dollars per share)	$ 65.30
Weighted-average remaining contractual life (years)	4 years	5 years	5 years 2 months 12 days	7 years
Exercisable, weighted-average remaining contractual life (years)	4 years
Aggregate intrinsic value	$ 93	$ 755	$ 4,398	$ 11,947
Exercisable, aggregate intrinsic value	$ 93

The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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Period Type:	instant

- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.