Segment Reporting (Details Textuals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2015
Segment Reporting Information [Line Items]
Other than temporary asset impairment charges	$ 18,294	$ 35,648
Expense recognized for the donation of the corporate headquarters	40,730
Non capitalizable transaction cost	$ 88,316