Debt - 2010 Convertible Notes (Details Textual) (USD $)	12 Months Ended			12 Months Ended			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2010	Dec. 31, 2013 Senior subordinated Convertible Notes 2010	Dec. 31, 2010 Senior subordinated Convertible Notes 2010	Mar. 01, 2010 Senior subordinated Convertible Notes 2010	Dec. 31, 2010 Senior subordinated Convertible Notes 2010 Pre August Dividend	Dec. 31, 2010 Senior subordinated Convertible Notes 2010 Post August Dividend	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 (Textual) [Abstract]
Senior subordinated convertible notes face amount											$ 150,000,000
Interest rate on senior subordinated convertible notes			3.00%						3.00%		3.00%
Notes Issuance price percentage of par value	100.00%
Maturity date of 2010 Convertible Notes					Mar. 01, 2017
Initial conversion price	$ 24.01						$ 24.45	$ 24.01
Initial conversion rate of common stock							40.8998	41.6555
Convertible Notes, initial conversion of Par Value Convertible Notes to common stock							1,000	1,000
Trade Price of common stock					$ 31.21
Percent of Trade Price of common stock to initial conversion price					130.00%
Average Conversion Value for the 2010 Convertible Notes				98.00%
Conversion obligation settlement in cash	100.00%
Conversion obligation exceeded the par value	34,000,000
Long-term debt, unamortized original issue discount	$ 19,950,000	$ 25,302,000				$ 38,400,000			$ 19,950	$ 25,302
Effective interest rate of the liability			7.75%