Impairment Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Goodwill impairment	$ 0	$ 23,574
Impairment loss	8,911	28,243
Deferred tax benefit	$ 17,268	3,359	$ 4,559
EquipmentOne [Member]
Property, Plant and Equipment [Line Items]
Goodwill impairment		23,574
Deferred tax benefit		1,798
Customer Relationships [Member] | EquipmentOne [Member]
Property, Plant and Equipment [Line Items]
Impairment loss		$ 4,669