DERIVATIVE INSTRUMENTS (Details)	8 Months Ended		12 Months Ended
	Dec. 31, 2018 USD ($) derivative_instrument	Dec. 31, 2017 USD ($)	Apr. 30, 2018 USD ($)	Apr. 30, 2017 USD ($)	Apr. 30, 2016 USD ($)	Jan. 31, 2023 USD ($) derivative_instrument
Derivative [Line Items]
Cash flow hedge gain (loss) to be reclassified within twelve months	$ 61,000
Interest expense	21,359,000	$ 22,804,000	$ 34,178,000	$ 34,314,000	$ 28,417,000
Net income (loss)	(5,320,000)	$ 140,594,000	127,629,000	30,525,000	$ 76,602,000
Designated as Hedging Instrument
Derivative [Line Items]
Derivative instrument - interest rate swap	818,000		1,779,000	0
Derivative Liability	1,675,000		0	0
Gain (Loss) Recognized in OCI	(2,794,000)		1,627,000	0
Designated as Hedging Instrument | Interest Rate Contract
Derivative [Line Items]
Gain (Loss) Recognized in OCI	$ (2,794,000)		1,627,000	0
Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Number of instruments held | derivative_instrument	2
Notional amount	$ 145,000,000
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest | Reclassification out of Accumulated Other Comprehensive Income
Derivative [Line Items]
Net income (loss)	(159,000)		(152,000)	0
Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest | Reclassification out of Accumulated Other Comprehensive Income | Interest Rate Contract
Derivative [Line Items]
Interest expense	(159,000)		(152,000)	0
Other Assets | Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Derivative instrument - interest rate swap	818,000		1,779,000	0
Accounts Payable and Accrued Expenses | Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Derivative Liability	$ 1,675,000		$ 0	$ 0
Scenario, Forecast | Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Number of instruments held | derivative_instrument						1
Notional amount						$ 70,000,000