Summary of Significant Accounting Policies (Fair Value of Derivatives Embedded within Convertible Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Embedded Derivative [Line Items]
Fair market value of embedded derivatives at the midpoint of the inputs	$ 112,332	$ 144,042
Minimum
Embedded Derivative [Line Items]
Fair market value of embedded derivatives at the midpoint of the inputs	111,653	143,422
Maximum
Embedded Derivative [Line Items]
Fair market value of embedded derivatives at the midpoint of the inputs	$ 113,090	$ 144,660