Detail of Certain Balance Sheet Accounts Detail of Certain Balance Sheet Accounts (Property and Equipment) (Details Textual) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Capital expenditures incurred for purchase and construction of assets	$ 33,000
Capital Expenditures Incurred but Not yet Paid	6,066	$ 7,287	$ 8,800
Land and Building [Member]
Property, Plant and Equipment [Line Items]
Acquisition of fixed assets	12,200
Land and Building [Member]
Property, Plant and Equipment [Line Items]
Acquisition of fixed assets	$ 8,900