STOCKHOLDERS' EQUITY: Future expense, by award type (Details) $ in Millions	Mar. 31, 2020 USD ($)
Share-based compensation
Total	$ 172.1
2021
Share-based compensation
Total	80.4
2022
Share-based compensation
Total	57.7
2023
Share-based compensation
Total	27.8
2024
Share-based compensation
Total	6.2
Stock options
Share-based compensation
Share-based compensation not yet recognized	3.8
Stock options | 2021
Share-based compensation
Share-based compensation not yet recognized	2.3
Stock options | 2022
Share-based compensation
Share-based compensation not yet recognized	1.1
Stock options | 2023
Share-based compensation
Share-based compensation not yet recognized	0.4
Stock options | 2024
Share-based compensation
Share-based compensation not yet recognized	0.0
Restricted stock units
Share-based compensation
Future share-based compensation expense expected	122.5
Restricted stock units | 2021
Share-based compensation
Future share-based compensation expense expected	51.7
Restricted stock units | 2022
Share-based compensation
Future share-based compensation expense expected	39.3
Restricted stock units | 2023
Share-based compensation
Future share-based compensation expense expected	25.3
Restricted stock units | 2024
Share-based compensation
Future share-based compensation expense expected	6.2
Consideration Holdback | Data Plus Math Corporation
Share-based compensation
Future share-based compensation expense expected	18.6
Consideration Holdback | Data Plus Math Corporation | 2021
Share-based compensation
Future share-based compensation expense expected	8.3
Consideration Holdback | Data Plus Math Corporation | 2022
Share-based compensation
Future share-based compensation expense expected	8.2
Consideration Holdback | Data Plus Math Corporation | 2023
Share-based compensation
Future share-based compensation expense expected	2.1
Consideration Holdback | Data Plus Math Corporation | 2024
Share-based compensation
Future share-based compensation expense expected	0.0
Pacific Data Partners, LLC Agreement Plan | Pacific Data Partners LLC
Share-based compensation
Future share-based compensation expense expected	27.2
Pacific Data Partners, LLC Agreement Plan | Pacific Data Partners LLC | 2021
Share-based compensation
Future share-based compensation expense expected	18.1
Pacific Data Partners, LLC Agreement Plan | Pacific Data Partners LLC | 2022
Share-based compensation
Future share-based compensation expense expected	9.1
Pacific Data Partners, LLC Agreement Plan | Pacific Data Partners LLC | 2023
Share-based compensation
Future share-based compensation expense expected	0.0
Pacific Data Partners, LLC Agreement Plan | Pacific Data Partners LLC | 2024
Share-based compensation
Future share-based compensation expense expected	$ 0.0