Fair Value Measurements (Narrative) (Details) - USD ($)	3 Months Ended
Nov. 30, 2020	May 31, 2020	Nov. 30, 2019
Percentage of marketable securities investments mature within one year	72.00%
Percentage of marketable securities investments mature within one to three years	28.00%
Fair Value, Measurements, Nonrecurring [Member]
Assets fair value adjustments	$ 0		$ 0
Liabilities fair value adjustments	$ 0		$ 0
Net Irrigate, LLC [Member]
Earn-out liability payment period		1 year
Maximum potential payout		$ 1,500,000

Business combination contingent consideration maximum potential earnout payment.

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Business combination earn-out liability payment period.

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Percentage of marketable securities investments mature within one to three years.

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Percentage of marketable securities investments mature within one year.

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Amount of addition (reduction) to the amount at which an asset could be incurred (settled) in a current transaction between willing parties.

No definition available.

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Amount of addition (reduction) to the amount at which a liability could be incurred (settled) in a current transaction between willing parties.

No definition available.

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