Operating Expenses (Schedule of Depreciation and Amortization Expenses) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Expenses [Abstract]
Depreciation expense	$ 29,021	$ 28,337	$ 30,983
Amortization expense	37,593	24,357	9,878
Total depreciation and amortization expenses	$ 66,614	$ 52,694	$ 40,861