Operating Expenses (Schedule of Depreciation and Amortization Expenses) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Operating Expenses [Abstract]
Depreciation expense	$ 7,751	$ 8,491	$ 23,466	$ 26,718
Amortization expense	2,445	1,526	7,094	4,684
Total depreciation and amortization expenses	$ 10,196	$ 10,017	$ 30,560	$ 31,402