DEBT Narrative (Detail)		3 Months Ended			9 Months Ended
	Jul. 21, 2014 USD ($) $ / shares $ / unit shares	Sep. 30, 2016 USD ($) $ / shares	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2016 USD ($) d $ / shares	Sep. 30, 2015 USD ($)	Aug. 15, 2014 USD ($)
Debt Instrument [Line Items]
Amortization of discount on convertible debt					$ 4,700,000	$ 3,842,000
Write-off of deferred financing costs					340,000	0
Convertible Senior 2019 Notes [Member] | Convertible Debt [Member]
Debt Instrument [Line Items]
Initial issued principal amount	$ 130,000,000						$ 19,500,000
Total principal amount	$ 149,500,000	$ 149,500,000			$ 149,500,000
Interest rate per annum	2.50%
Threshold Trading Days (Whether or Not Consecutive) | d					20
Threshold Consecutive Trading Days					30 days
Threshold Percentage of Stock Price Trigger					130.00%
Principal Amount of Convertible Notes	$ 1,000
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%
Deferred Finance Costs, Gross	$ 4,600,000
Financing costs of equity component	1,100,000
Long-term Debt	122,100,000	$ 130,900,000			$ 130,900,000
Debt discount	27,400,000	16,000,000			16,000,000
Unamortized deferred financing costs		2,600,000			2,600,000
Fair value of liability component of Notes		133,900,000			133,900,000
Interest expense recognized on debt agreement		2,500,000	$ 2,500,000		7,500,000	7,400,000
Amortization of discount on convertible debt		1,300,000	1,300,000		4,000,000	3,800,000
Amortization of Financing Costs		200,000	$ 200,000		700,000	$ 700,000
Payments for Hedging Activities	$ 18,400,000
Derivative, Cap Price | $ / unit	19.38
Issuance cost of convertible senior notes and revolving credit facility				$ 5,700,000
The Revolver [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity, revolving credit facility	$ 42,500,000	20,000,000			20,000,000
Maturity date period, revolving credit facility	180 days
The Revolver [Member] | Revolving Credit Facility [Member] | Swing Line [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity, revolving credit facility	$ 10,000,000
The Revolver [Member] | Revolving Credit Facility [Member] | Letter of Credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity, revolving credit facility	$ 15,000,000
Interest Expense [Member] | The Revolver [Member] | Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Unamortized deferred financing costs		$ 300,000			$ 300,000