Equity-Based Compensation Plans (Details Textual) (USD $)	3 Months Ended		9 Months Ended			9 Months Ended						9 Months Ended		12 Months Ended		9 Months Ended		12 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	May 10, 2012	Sep. 30, 2012 Stock option grants in 2011 and 2012 [Member]	Sep. 30, 2012 Stock option grants in 2006 through 2010 [Member]	Sep. 30, 2012 Performance Shares [Member]	Sep. 30, 2011 Performance Shares [Member]	Sep. 30, 2012 Restricted Stock Units R S U [Member]	Sep. 30, 2011 Restricted Stock Units R S U [Member]	Sep. 30, 2012 Restricted Stock [Member]	Sep. 30, 2011 Restricted Stock [Member]	Dec. 31, 2011 Maximum [Member]	Dec. 31, 2010 Maximum [Member]	Sep. 30, 2012 Maximum [Member] Performance Shares [Member]	Sep. 30, 2012 Maximum [Member] Restricted Stock Units R S U [Member]	Dec. 31, 2011 Minimum [Member]	Dec. 31, 2010 Minimum [Member]	Sep. 30, 2012 Minimum [Member] Performance Shares [Member]	Sep. 30, 2012 Minimum [Member] Restricted Stock Units R S U [Member]	Sep. 30, 2012 Selling General and Administrative Expenses [Member]	Sep. 30, 2011 Selling General and Administrative Expenses [Member]	Sep. 30, 2012 Selling General and Administrative Expenses [Member]	Sep. 30, 2011 Selling General and Administrative Expenses [Member]
Equity-Based Compensation Plans (Textual) [Abstract]
Equity-based compensation expense			$ 5,722,000	$ 5,863,000																		$ 2,300,000	$ 1,900,000	$ 5,700,000	$ 5,900,000
Non-cash compensation expense		400,000
Stock option vesting Period						3 years	4 years									3 years	5 years			1 year	3 years
Stock option vesting rights						three-year period	four-year period
Number of Options, Exercised			(1,200)
Intrinsic value of options				1,900,000
Unrecognized compensation expense	3,200,000		3,200,000
Compensation expense recognized over a weighted-average period			1 year 5 months					1 year 2 months	2 years 1 month			2 years 7 months	3 years 3 months
Fair Value of Vested Options			3,500,000
Performance share units vesting period			P3Y
Performance share units granted														200.00%	150.00%			0.00%	0.00%
Unrecognized compensation cost total								2,000,000	1,700,000	4,900,000	6,200,000
Intrinsic Value of restricted stock awards												4,154,419
Number of shares of common stock available for issuance	650,000		650,000
Deferred Compensation Arrangement with Individual, Common Stock Reserved for Future Issuance	295,631		295,631
Stock & Deferred Compensation Plan for Non-Employee			56,264
Weighted-average fair value			$ 7.73
Approximate cash payment to each non-employee for insufficient deferred stock units			$ 28,100
Share units outstanding under the plan	243,982		243,982
Increasing in aggregate number of shares of common stock available for issuance					350,000
ESPP under which the offering purchase price of shares	85.00%
Offering Period of Employee Stock Purchase Plan			3 months
Stock issued under ESPP			327,884
Company issued common stock under its ESPP	15.00%
Authorization of additional shares under ESPP					1,800,000