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ACQUISITION - Cantaloupe Systems, Inc. (Details) - USD ($) $ in Thousands		3 Months Ended												6 Months Ended		9 Months Ended		12 Months Ended			36 Months Ended
	Nov. 09, 2017	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2017	Dec. 31, 2016	Mar. 31, 2018	Mar. 31, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2019
Business Acquisition [Line Items]
Principal amount	$ 35,000
Weighted average useful life																		12 years 3 months 1 day
Goodwill		$ 64,149				$ 64,149	$ 64,149	$ 64,403	$ 11,492	$ 11,492	$ 11,492	$ 11,492	$ 11,703	$ 64,403	$ 11,492	$ 64,149	$ 11,492	$ 64,149	$ 64,149	$ 11,492	$ 64,149
Net earnings		$ (10,541)	$ (4,510)	$ (10,657)	$ (6,320)	$ (1,696)	$ (3,223)	$ (4,194)	$ (2,171)	$ (2,938)	$ (925)	$ (232)	$ (3,370)	$ (6,365)	$ (3,602)	$ (9,588)	$ (4,527)	$ (32,028)	(11,284)	(7,465)	$ (50,800)
Cantaloupe
Business Acquisition [Line Items]
Total consideration	88,207
Intangible assets	30,800
Weighted average useful life																		13 years
Goodwill	52,658
Acquiree revenue																			19,200
Net earnings																			$ 200
Customer Relationships
Business Acquisition [Line Items]
Weighted average useful life																		16 years 3 months 1 day
Customer Relationships \| Cantaloupe
Business Acquisition [Line Items]
Intangible assets	18,900
Developed Technology Rights \| Cantaloupe
Business Acquisition [Line Items]
Intangible assets	10,300
Trade Names \| Cantaloupe
Business Acquisition [Line Items]
Intangible assets	1,600
Term Loan
Business Acquisition [Line Items]
Principal amount	25,000
Revolving Credit Facility
Business Acquisition [Line Items]
Principal amount	$ 10,000
Minimum \| Cantaloupe
Business Acquisition [Line Items]
Useful lives																		6 years
Minimum \| Customer Relationships
Business Acquisition [Line Items]
Useful lives																		10 years	10 years
Maximum \| Cantaloupe
Business Acquisition [Line Items]
Useful lives																		18 years
Maximum \| Customer Relationships
Business Acquisition [Line Items]
Useful lives																		18 years	18 years
Excluded from unaudited pro forma earnings \| Cantaloupe
Business Acquisition [Line Items]
Integration and acquisition costs																			$ 7,100	$ 7,100