DEBT - Additional Information (Detail)				3 Months Ended		6 Months Ended
	May 16, 2018 USD ($)	Apr. 13, 2018 USD ($)	Jul. 21, 2014 USD ($) $ / shares shares	Jun. 30, 2018 USD ($) $ / shares	Jun. 30, 2017 USD ($)	Jun. 30, 2018 USD ($) d $ / shares	Jun. 30, 2017 USD ($)	May 31, 2018 USD ($)
Debt Instrument [Line Items]
Total debt				$ 312,608,000		$ 312,608,000
Repayments of Senior Debt						131,625,000	$ 0
Cash paid for interest	$ 1,100,000					8,964,000	4,007,000
Loss on extinguishment of debt						11,429,000	0
Gain (Loss) on Extinguishment of Debt				(11,429,000)	$ 0	(11,429,000)	0
Non-cash interest expense						3,100,000	3,474,000
Amortization of Financing Costs				100,000
Interest expense, net				$ 5,907,000	4,914,000	$ 10,734,000	7,523,000
Convertible Senior 2019 Notes [Member] | Convertible Debt [Member]
Debt Instrument [Line Items]
Initial issued principal amount			$ 149,500,000
Effective interest rate			2.50%	7.50%		7.50%
Total debt		$ 149,500,000		$ 22,608,000		$ 22,608,000
Principal Amount of Convertible Notes		1,000	$ 1,000
Repayments of Senior Debt	$ 126,900,000					126,900,000
Debt Instrument, Fee Amount		700,000
Write Off Of Unamortized Discount (Premium)		5,900,000
Loss on extinguishment of debt		$ 900,000
Gain (Loss) on Extinguishment of Debt				$ 7,500,000		$ (7,500,000)
Threshold Trading Days (Whether or Not Consecutive) | d						20
Threshold Consecutive Trading Days | d						30
Threshold Percentage of Stock Price Trigger						130.00%
Maximum Percent of Conversion Rate for Each Trading Day			98.00%
Initial conversion rate | shares			67.41
Initial conversion price | $ / shares			$ 14.83	$ 14.83		$ 14.83
Repurchase price percentage of principal						100.00%
Debt discount				$ 1,000,000		$ 1,000,000
Unamortized deferred financing costs				100,000		100,000
Long-term Debt				21,500,000		21,500,000
Fair value of liability component of Notes				21,900,000		21,900,000
Interest expense recognized on debt agreement				1,500,000		4,100,000	5,100,000
Non-cash interest expense				$ 800,000	1,400,000	2,300,000	2,800,000
Amortization of Financing Costs					200,000	$ 400,000	$ 500,000
Interest expense, net					$ 2,600,000
Debt Instrument, Capped Call Transaction, Cash Settlement								$ 2,100,000