Operating Expenses (Schedule of Depreciation and Amortization Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Operating Expenses [Abstract]
Depreciation expense	$ 6,793	$ 7,932	$ 13,585	$ 15,715
Amortization expense	5,079	2,352	8,625	4,649
Total depreciation and amortization expenses	$ 11,872	$ 10,284	$ 22,210	$ 20,364