ACQUISITION - Fair Value of Net Assets (Details) - USD ($) $ in Thousands	9 Months Ended
	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill	$ 116,217		$ 50,209	$ 50,209
SingleHop, LLC
Business Acquisition [Line Items]
Cash	2,823	$ 2,857
Measurement period adjustment, cash	(34)
Prepaid expenses and other assets	2,227	1,683
Measurement period adjustment, prepaid expenses and other assets	544
Property and equipment	14,253	14,885
Measurement period adjustment, property, plant and equipment	(632)
Other assets	576	39
Measurement period adjustment, other long term assets	537
Goodwill	66,008	67,868
Measurement period adjustment, goodwill	(1,860)
Total assets acquired	140,787	142,232
Measurement period adjustment, total assets acquired	(1,445)
Accounts payable and accrued liabilities	2,819	5,098
Measurement period adjustment, accounts payable and accrued liabilities	(2,279)
Deferred revenue	2,434	1,600
Measurement period adjustment, deferred revenue	834
Long term liabilities	534	534
Measurement period adjustment, long term liabilities	0
Net assets acquired	135,000	135,000
Measurement period adjustment, net assets acquired	0
Noncompete agreements | SingleHop, LLC
Business Acquisition [Line Items]
Customer relationships	4,000	4,000
Measurement period adjustment, intangible assets	0
Trade names | SingleHop, LLC
Business Acquisition [Line Items]
Customer relationships	1,700	1,700
Measurement period adjustment, intangible assets	0
Technology | SingleHop, LLC
Business Acquisition [Line Items]
Customer relationships	15,100	15,100
Measurement period adjustment, intangible assets	0
Customer relationships | SingleHop, LLC
Business Acquisition [Line Items]
Customer relationships	34,100	$ 34,100
Measurement period adjustment, intangible assets	$ 0