Commitments and Contingencies (Narrative) (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Increase (decrease) in contractual obligations not reflected in the balance sheet	$ 46,255
Contractual Obligation	1,363,852
Loss Contingency, Damages Sought, Value	$ 280,000