Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Non cash investing and financing activities:
Common stock issuance for conversion and exchange in 2014 and 2013, respectively, of 6.0% convertible senior subordinated notes due April 2014, $150 million related party in 2013	$ 56,350	$ 193,650
6.0% Convertible senior subordinated notes, due April 2014 (2)
Non cash investing and financing activities:
Interest rate of convertible subordinated notes	6.00%	6.00%
Related Party [Member] | 6.0% Convertible senior subordinated notes, due April 2014 (2)
Non cash investing and financing activities:
Common stock issuance for conversion and exchange in 2014 and 2013, respectively, of 6.0% convertible senior subordinated notes due April 2014, $150 million related party in 2013	$ 0	$ 0