Convertible Notes, Long -Term Debt and Credit Facility (Details Textual) (USD $)	1 Months Ended		9 Months Ended										3 Months Ended	9 Months Ended	1 Months Ended			9 Months Ended		9 Months Ended	1 Months Ended	3 Months Ended	9 Months Ended		9 Months Ended			3 Months Ended
	Nov. 30, 2011	Jun. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Jun. 30, 2012	Jun. 25, 2012	Dec. 31, 2011	Sep. 23, 2011	Mar. 31, 2010	Mar. 30, 2010	Feb. 29, 2008	Feb. 11, 2008	Mar. 31, 2010 Term loan [Member]	Sep. 30, 2012 Term loan [Member]	Jun. 30, 2011 2008 Notes [Member]	May 31, 2011 2008 Notes [Member]	Feb. 14, 2008 2008 Notes [Member]	Sep. 30, 2012 2008 Notes [Member]	Jun. 25, 2012 2008 Notes [Member]	Sep. 30, 2012 Senior credit facility [Member]	Jan. 31, 2012 2010 Notes [Member]	Mar. 31, 2010 2010 Notes [Member]	Sep. 30, 2012 2010 Notes [Member]	Jan. 05, 2012 2010 Notes [Member]	Sep. 30, 2012 Exchange agreement [Member]	Mar. 31, 2010 Exchange agreement [Member]	Mar. 30, 2010 Convertible Note [Member]	Mar. 31, 2010 Annual interest rate 12.5% [Member] Term loan [Member]	Sep. 23, 2011 Letters of Credit Sublimit [Member]	Sep. 30, 2012 Federal funds open rate [Member]	Sep. 30, 2012 One-Month LIBOR Rate [Member]	Sep. 30, 2012 One two or three month LIBOR rate [Member]
Line of Credit Facility [Line Items]
Credit facility, current borrowing capacity								$ 35,000,000
Credit facility, remaining borrowing capacity																													5,000,000
Credit facility, variable percentage rate spread			1.00%																											1.50%	2.00%	2.00%
Debt instrument, principal amount																	115,000,000
Term loan, face amount													40,000,000
Convertible notes, interest rate																	5.25%					5.25%
Convertible notes maturity date			Nov. 01, 2012															Feb. 15, 2028					Feb. 15, 2028
Nonconvertible debt borrowing interest rate																		11.50%
Expected term for accretion of associated debt discount (in years)																		5 years
Contractual call/put options, exercisable date																		Feb. 15, 2013
Discount on notes			1,438,000				6,766,000										27,800,000
Deferred tax liability on notes																	10,600,000
Percentage of original principal amount of notes plus accrued and unpaid interest equalized repurchase																			102.00%					104.95%
Debt instrument, maturity date			Nov. 01, 2012															Feb. 15, 2028					Feb. 15, 2028
Senior credit facility, value of common stock converted									50,000,000																	2,000,000
Convertible notes for each $1,000 principal amount, amount of notes exchanged																		40,000,000
Convertible notes for each $1,000 principal amount, amount of aggregate consideration																							36,000,000
Redeemable price as a percentage of outstanding principal note amount			100.00%																		104.95%
Amount of notes exchanged																4,500,000					36,000,000
Loss on the extinguishment of debt		2,100,000	1,000,000											2,100,000		1,100,000					5,400,000
Cash premium loss recognized on conversion of debt			2,862,000	3,963,000											300,000						1,800,000
Contingent interest percentage on principal amount of notes, minimum																									120.00%
Contingent interest payable rate																									0.50%
Common stock, shares issued			52,918,524				51,957,652																				1,568,867
Convertible notes for each $1,000 principal amount, number of shares																559,007
Term loan, quarterly principal payments													1,000,000
Term loan, annual interest rate																												12.50%
Convertible notes for each $1000 principal amount, principal amount of 2010 Notes converted																						900
Senior note commitment fee																				7,300,000
Return of borrowed shares under share-based, shares	701,102	659,340
Convertible Notes Long Term Debt and Credit Facility (Textual) [Abstract]
Credit facility, expiration date			Dec. 15, 2012
Credit facility, variable percentage rate spread			1.00%																											1.50%	2.00%	2.00%
Credit facility, extended maturity date			September 22, 2014
Credit facility, interest rate at period end			4.25%
Credit facility, commitment fee percentage			0.25%
Credit facility, financial covenant debt ratio upper range			110.00%
Credit facility, financial covenant debt ratio lower range			100.00%
Credit facility, covenant terms			The Credit Facility is secured by substantially all of the Company’s personal property, including accounts receivable, inventory, equipment and other intangible assets and contains customary representations, warranties, and both affirmative and negative covenants, including a financial covenant to maintain consolidated earnings before interest, taxes, depreciation and amortization (“EBITDA”) to debt ratio of 1.10 to 1.00 and an annual limit on capital expenditures. The Credit Facility restricts the payment of cash dividends on common stock. In the event of default, the Lender may accelerate the maturity date of outstanding amounts borrowed under the Credit Facility.
Credit facility, interest rate description			Interest on borrowings under the Credit Facility is calculated daily at the higher of (a) the commercial lending base rate of PNC Bank plus 1%, (b) the federal funds open rate plus 1.5%, and (c) the daily one-month LIBOR rate plus 2%. The interest rate on borrowings would have been 4.25% at September 30, 2012. The Company may elect to borrow any amount available under the Credit Facility for a term of one, two or three months at LIBOR plus 2%.
Effective tax rate			38.00%
Convertible notes for each $1,000 principal amount, volume-weighted average price of common stock rate									95.00%
Convertible notes for each $1,000 principal amount, number of preceding trading days					5 days				10 days
Convertible notes for each $1,000 principal amount, number of shares			43.9560
Convertible notes for each $1,000 principal amount, conversion price per share			$ 22.75
Assumed rate of accretion on notes										9.90%
Convertible notes for each $1,000 principal amount, third-party transaction costs			800,000
Share lending agreement, number of common stock shares loaned			3,800,000									3,800,000
Own share lending arrangement nominal loan fee per share											$ 0.0001
Borrowed shares outstanding			2,439,558
Share lending agreement, fair value			500,000
Common shares not subject to the share lending arrangement, fair value			30,900,000
Capital lease obligations			1,890,000				1,642,000
Notes repurchased						$ 15,000,000