LONG-TERM DEBT (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	9 Months Ended		1 Months Ended	3 Months Ended		9 Months Ended			1 Months Ended									3 Months Ended	9 Months Ended	1 Months Ended	9 Months Ended	1 Months Ended		1 Months Ended	3 Months Ended		9 Months Ended			1 Months Ended			9 Months Ended		1 Months Ended
	Dec. 31, 2011	Dec. 31, 2011	Dec. 31, 2010	Oct. 31, 2011 Credit Agreement	Dec. 31, 2011 Credit Agreement	Dec. 31, 2010 Credit Agreement	Dec. 31, 2011 Credit Agreement Numerator Denominator	Dec. 31, 2010 Credit Agreement	Mar. 31, 2011 Credit Agreement	Oct. 31, 2011 Credit Agreement Maximum	Oct. 31, 2011 Credit Agreement Minimum	Dec. 31, 2011 Credit Agreement Base rate	Oct. 31, 2011 Credit Agreement Base rate Maximum	Oct. 31, 2011 Credit Agreement Base rate Minimum	Dec. 31, 2011 Credit Agreement LIBOR	Oct. 31, 2011 Credit Agreement LIBOR Maximum	Oct. 31, 2011 Credit Agreement LIBOR Minimum	Nov. 30, 2011 1.75% Convertible Notes due 2016 ("1.75% Convertible Notes") D	Dec. 31, 2011 1.75% Convertible Notes due 2016 ("1.75% Convertible Notes")	Dec. 31, 2011 1.75% Convertible Notes due 2016 ("1.75% Convertible Notes")	Nov. 30, 2011 1.75% Convertible Notes due 2016 ("1.75% Convertible Notes") Conversion Terms at Holder's Option D	Dec. 31, 2011 1.75% Convertible Notes due 2016 ("1.75% Convertible Notes") Conversion Terms Upon Occurrence of Certain Fundamental Company Changes	Nov. 30, 2011 1.75% Convertible Notes due 2016 ("1.75% Convertible Notes") Conversion Terms, Event of Default	Dec. 31, 2011 Prior Credit Agreement	Jun. 30, 2009 4.375% convertible senior notes due 2014 ("Convertible Notes")	Dec. 31, 2011 4.375% convertible senior notes due 2014 ("Convertible Notes")	Dec. 31, 2010 4.375% convertible senior notes due 2014 ("Convertible Notes")	Dec. 31, 2011 4.375% convertible senior notes due 2014 ("Convertible Notes")	Dec. 31, 2010 4.375% convertible senior notes due 2014 ("Convertible Notes")	Mar. 31, 2011 4.375% convertible senior notes due 2014 ("Convertible Notes")	Jun. 30, 2009 4.375% convertible senior notes due 2014 ("Convertible Notes") 4.375% Convertible Note hedge options	Jun. 30, 2009 4.375% convertible senior notes due 2014 ("Convertible Notes") 4.375% Convertible Note hedge warrants	Jun. 30, 2009 4.375% convertible senior notes due 2014 ("Convertible Notes") Conversion Terms at Holder's Option D	Dec. 31, 2011 4.375% convertible senior notes due 2014 ("Convertible Notes") Redemption Terms at Company Option D	Dec. 31, 2011 4.375% convertible senior notes due 2014 ("Convertible Notes") Conversion Terms Upon Occurrence of Certain Fundamental Company Changes	Jun. 30, 2009 4.375% convertible senior notes due 2014 ("Convertible Notes") Conversion Terms, Event of Default
Credit Agreement
Maximum borrowing capacity				$ 100,000																				$ 140,000
Interest rate, variable rate basis												5.25%	2.00%	1.50%	3.30%	3.00%	2.50%
Credit Agreement Availability
Available borrowings					98,218		98,218		115,503
Outstanding letters of credit					1,664		1,664		1,664
Interest expense and fees					215	443	1,090	1,340
Increase additional borrowings				40,000
Interest coverage ratio for trailing twelve month period, numerator							1
Interest coverage ratio for trailing twelve month period, denominator							1
Maximum liquidity level triggering the requirement to maintain an interest coverage ratio of one to one							30,000
Monthly fee on unused available balance (as a percent)										0.50%	0.375%
Convertible Notes
Aggregate principal amount																		250,000							138,000
Interest rate on convertible notes (as a percent)																		1.75%	1.75%	1.75%					4.375%	4.375%		4.375%
Amount pertaining to exercise of over-allotment of debt by underwriters																		30,000							18,000
Initial conversion rate of common stock per $1 of principal amount of Convertible Notes (in shares)																		52.3745							93.6768
Principal amount used for debt instrument conversion ratio																		1							1
Initial conversion price of convertible notes into common stock (in dollars per share)																		$ 19.093							$ 10.675
Number of shares to be converted into common stock																		13,094,000							12,927,000
Minimum number of trading days triggering conversion of redemption feature																		20															20	20
The maximum period of consecutive trading days that the entity's common stock closing price to conversion price must exceed a specified percentage of conversion price to trigger conversion of redemption feature of notes																		30															30	30
Target ratio of closing share price to conversion price as a condition for conversion or redemption of Convertible Notes (as a percent)																		130.00%															130.00%	150.00%
Minimum consecutive business days in the measurement period the closing sales price of common stock must exceed a specified percentage of conversion price to trigger conversion feature of note																					5												5
The maximum period of trading days in the measurement period that the entity's common stock closing price to conversion price must exceed a specified percentage of conversion price to trigger conversion feature of notes																					10												10
Ratio of closing share price to conversion price as a condition for conversion of Convertible Notes, minimum (as a percent)																					98.00%												98.00%
Redemption price as percentage of principal amount of notes plus accrued and unpaid interest																						100.00%	100.00%											100.00%	100.00%	100.00%
Minimum percentage of aggregate principal amount held by bondholders to declare notes due and payable																							25.00%													25.00%
In event of default arising out of certain bankruptcy events, the percentage of principal amount due and payable																							100.00%													100.00%
Adjustment to additional paid-in capital for options to purchase common stock																															43,600
Investment warrants exercise price	$ 14.945																															$ 14.945
Number of shares of common stock that will be settled against warrants																																12,927,000
Total proceeds from warrants credited to additional paid-in capital																																26,300
Banking, legal and accounting fees related to issuance of convertible notes																			6,875	6,875					3,410
Estimated fair value																			197,373	197,373
Non-convertible borrowing rate (as a percent)																			6.90%	6.90%
Derivative nonmonetary notional amount (in shares)																															12,927,000
Investment options exercise price																															$ 10.675
Carrying amount of the equity component																				52,627
Banking, legal and accounting fees related to issuance of convertible notes allocated to the liability component																				5,428
Banking, legal and accounting fees related to issuance of convertible notes allocated to the equity component																				1,447
Additional information related to convertible notes
Additional paid-in capital																			51,180	51,180						42,018		42,018		42,018
Principal amount of Convertible Notes																			250,000	250,000						138,000		138,000		138,000
Unamortized discount of the liability component																			51,524	51,524						24,570		24,570		30,761
Net carrying amount of Convertible Notes																			198,476	198,476						113,430		113,430		107,239
Carrying amount of debt issuance costs																			5,277	5,277						1,649		1,649		2,161
Components of interest expense
Cash interest expense (coupon interest expense)																			547	547						1,509	1,509	4,527	4,494
Non-cash amortization of discount on Convertible Notes		7,294	5,440																1,103	1,103						2,131	1,872	6,191	5,440
Amortization of debt issuance costs		1,014	939																151	151						171	171	512	512
Total interest expense related to Convertible Notes																			1,801	1,801						3,811	3,552	11,230	10,446
Interest
2013																			4,557	4,557
2014																			4,375	4,375
2015																			4,375	4,375
2016																			4,375	4,375
Thereafter																			4,375	4,375
Total																			22,057	22,057
Principal Repayments
Thereafter																			250,000	250,000
Total																			250,000	250,000						138,000		138,000		138,000
Total
2013																			4,557	4,557
2014																			4,375	4,375
2015																			4,375	4,375
2016																			4,375	4,375
Thereafter																			254,375	254,375
Total																			$ 272,057	$ 272,057