Summary of Significant Accounting Policies - Nature of Operations (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2016 USD ($) segment	Dec. 31, 2015 USD ($)
Financial instruments the Company measures at fair value on a recurring basis
Total assets	$ 1,961,532	$ 1,899,739
Nature of Operations
Number of business segments | segment	1
All Non-United States countries
Financial instruments the Company measures at fair value on a recurring basis
Total assets	$ 0
Revenue	$ 0