Accounts Receivable Insurance and Third Party Claims (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Total accounts receivable	$ 430,210	$ 375,993
Proceeds from insurance	1,600	15,200	$ 10,400
Accounts receivable - insurance and other third party claims [Member]
Total accounts receivable	10,753	$ 11,994
North American Operations [Member] | Accounts receivable - insurance and other third party claims [Member]
Total accounts receivable	5,900
U.K./European Operations [Member] | Accounts receivable - insurance and other third party claims [Member]
Total accounts receivable	4,300
Australian Operations [Member] | Accounts receivable - insurance and other third party claims [Member]
Total accounts receivable	$ 600