Summary of Significant Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Basic earnings per share computation:
Net income (loss) - basic	$ 9,376	$ (345)	$ 15,931	$ (178)
Weighted average common shares - basic	52,861,167	47,107,094	52,851,587	46,967,688
Basic earnings (loss) per share	$ 0.18	$ (0.01)	$ 0.30	$ 0.00
Dilutive earnings per share computation:
Net income (loss) - basic	$ 9,376	$ (345)	$ 15,931	$ (178)
Interest expense related to convertible 3.75% senior notes	1,348	0	2,695	0
Amortization of discount related to convertible 3.75% senior notes	1,643	0	3,233	0
Change in the fair value of derivative	(14,519)	0	(23,144)	0
Net income - diluted	$ (2,152)	$ (345)	$ (1,285)	$ (178)
Share Computation:
Weighted average common shares —basic	52,861,167	47,107,094	52,851,587	46,967,688
Effect of convertible 3.75% senior notes	12,732,168	0	12,732,168	0
Effect of dilutive stock options and warrants	1,532,570	0	1,590,791	0
Weighted average common shares outstanding —diluted	67,125,905	47,107,094	67,174,546	46,967,688
Diluted loss per share	$ (0.03)	$ (0.01)	$ (0.02)	$ 0.00