Stockholders' Equity - Stock Option Grants, Activity And Expense (Details) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2021 USD ($) individual $ / shares shares	Sep. 30, 2020 $ / shares shares
2009 Stock Option Plan
Granted (in shares)		111,258,000
Other Disclosures
Number of option holders | individual	18
Unrecognized compensation expense related to non-vested stock options that will be recognized during future periods
Balance of 2021 | $	$ 99
2022 | $	372
2023 | $	231
2024 | $	111
2025 | $	$ 15
INDUS stock option plan
Outstanding at beginning of period (in shares)	246,150,000	189,822,000
Adjustment for stock dividend (in shares)	5,413,000
Granted (in shares)		111,258,000
Exercised (in shares)	(15,422,000)	(44,900,000)
Forfeited (in shares)	(1,067,000)
Outstanding at end of period (in shares)	235,074,000	256,180,000
Weighted Avg. Exercise Price
Outstanding at beginning of period (in dollars per share) | $ / shares	$ 36.06	$ 28.23
Adjustment for stock dividend (in dollars per share) | $ / shares	34.29
Granted (in dollars per share) | $ / shares		45.72
Exercised (in dollars per share) | $ / shares	26.37	28.73
Forfeited (in dollars per share) | $ / shares	37.49
Outstanding at end of period (in dollars per share) | $ / shares	$ 35.85	$ 35.74
2020 Incentive Award Plan
2009 Stock Option Plan
Granted (in shares)	0
INDUS stock option plan
Granted (in shares)	0
2020 Incentive Award Plan | Non-employee directors
2009 Stock Option Plan
Granted (in shares)		111,258
INDUS stock option plan
Granted (in shares)		111,258
2020 Incentive Award Plan | Minimum | Non-employee directors
2009 Stock Option Plan
Fair values of stock options granted (in dollars per share) | $ / shares		$ 11.00
2020 Incentive Award Plan | Maximum | Non-employee directors
2009 Stock Option Plan
Fair values of stock options granted (in dollars per share) | $ / shares		$ 14.17