Income Taxes - Domestic and Foreign (Loss) Income before income taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Domestic and Foreign Income (Loss) before Income Taxes and income (loss) in equity method investments. [Line Items]
(Loss) income before income taxes and equity in earnings of joint venture	$ (143,745)	$ (60,744)	$ (15,542)
U.S.
Domestic and Foreign Income (Loss) before Income Taxes and income (loss) in equity method investments. [Line Items]
(Loss) income before income taxes and equity in earnings of joint venture	(112,904)	(55,611)	(28,398)
Segment, Geographical, Non-U.S. [Member]
Domestic and Foreign Income (Loss) before Income Taxes and income (loss) in equity method investments. [Line Items]
(Loss) income before income taxes and equity in earnings of joint venture	$ (30,841)	$ (5,133)	$ 12,856