Debt (Parenthetical) (Details) (USD $)					12 Months Ended			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010	Mar. 01, 2010 Senior subordinated Convertible Notes 2010	Dec. 31, 2013 2012 Credit Agreement	Dec. 31, 2013 2012 Credit Agreement Term Loan	Dec. 31, 2013 2012 Credit Agreement Revolving Loan	Dec. 31, 2013 2010 Convertible Notes Senior subordinated Convertible Notes 2010	Dec. 31, 2012 2010 Convertible Notes Senior subordinated Convertible Notes 2010	Dec. 31, 2010 2010 Convertible Notes Senior subordinated Convertible Notes 2010
Debt Instrument [Line Items]
Basis spread on term loan						2.00%
Term loan combined interest rate						2.25%
Maturity period						2017-11		2017-03
2012 Credit Agreement Early Termination Date					Dec. 01, 2016	Dec. 01, 2016
Amount available under revolving credit facility							$ 100,000,000
Interest rate on senior subordinated convertible notes			3.00%					3.00%		3.00%
Unamortized Original Issue Discount	$ 19,950,000	$ 25,302,000		$ 38,400,000				$ 19,950	$ 25,302