Segment Information Segments (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) region reportable_segment provinces	Mar. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of operating regions | region	8
Number of reportable segments | reportable_segment	3
Noncontrolling Interest, Ownership Percentage by Parent	51.10%
Operating revenue	$ 558,089	$ 574,661
Operating income/(loss)	79,710	86,913
Depreciation and amortization	62,626	65,990
Interest expense, net	27,063	24,738
Provision for/(benefit from) income taxes	14,260	(15,890)
Expenditures for Additions to Property and Equipment Net of Grants From Outside Parties	$ 61,293	52,288
North American Operations [Member]
Segment Reporting Information [Line Items]
Number of operating regions | provinces	6
Operating revenue	$ 332,446	325,630
Operating income/(loss)	69,315	73,160
Depreciation and amortization	38,431	40,631
Interest expense, net	12,401	8,455
Provision for/(benefit from) income taxes	14,087	(19,485)
Expenditures for Additions to Property and Equipment Net of Grants From Outside Parties	48,071	38,563
Australia Operations [Member]
Segment Reporting Information [Line Items]
Operating revenue	65,107	74,834
Operating income/(loss)	12,503	15,976
Depreciation and amortization	14,411	16,007
Interest expense, net	12,123	13,241
Provision for/(benefit from) income taxes	114	821
Expenditures for Additions to Property and Equipment Net of Grants From Outside Parties	2,849	5,262
U.K./European Operations [Member]
Segment Reporting Information [Line Items]
Operating revenue	160,536	174,197
Operating income/(loss)	(2,108)	(2,223)
Depreciation and amortization	9,784	9,352
Interest expense, net	2,539	3,042
Provision for/(benefit from) income taxes	59	2,774
Expenditures for Additions to Property and Equipment Net of Grants From Outside Parties	$ 10,373	$ 8,463
MIRA [Member]
Segment Reporting Information [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	48.90%