Segment Information Segments (Details) $ in Thousands, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) reportable_segment provinces region	Jun. 30, 2018 AUD ($)	Jun. 30, 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%		51.10%
Payments of Ordinary Dividends				$ 40.0
Payments of Ordinary Dividends, Parent				20.4	$ 15,600
Distribution to noncontrolling interest			$ 0	$ 19.6	14,900
Operating revenue	$ 571,480	$ 594,990	1,129,569		1,169,651
Operating income/(loss)	94,200	103,125	173,910		190,038
Depreciation and amortization	62,517	65,745	125,143		131,735
Interest expense, net	26,575	28,356	53,638		53,094
Provision for/(benefit from) income taxes	18,866	26,446	33,126		10,556
Cash expenditures for additions to property and equipment, net of grants from outside parties	68,566	68,139	$ 129,859		120,427
North American Operations [Member]
Segment Reporting Information [Line Items]
Number of operating regions | provinces			6
Operating revenue	341,847	339,557	$ 674,293		665,187
Operating income/(loss)	84,261	80,274	153,576		153,434
Depreciation and amortization	38,738	41,247	77,169		81,878
Interest expense, net	11,872	11,778	24,273		20,233
Provision for/(benefit from) income taxes	18,140	20,091	32,227		606
Cash expenditures for additions to property and equipment, net of grants from outside parties	52,649	48,924	100,720		87,487
Australia Operations [Member]
Segment Reporting Information [Line Items]
Operating revenue	66,531	79,029	131,638		153,863
Operating income/(loss)	11,655	25,896	24,158		41,872
Depreciation and amortization	14,192	15,288	28,603		31,295
Interest expense, net	11,800	12,893	23,923		26,134
Provision for/(benefit from) income taxes	(44)	3,901	70		4,722
Cash expenditures for additions to property and equipment, net of grants from outside parties	9,103	14,489	11,952		19,751
U.K./European Operations [Member]
Segment Reporting Information [Line Items]
Operating revenue	163,102	176,404	323,638		350,601
Operating income/(loss)	(1,716)	(3,045)	(3,824)		(5,268)
Depreciation and amortization	9,587	9,210	19,371		18,562
Interest expense, net	2,903	3,685	5,442		6,727
Provision for/(benefit from) income taxes	770	2,454	829		5,228
Cash expenditures for additions to property and equipment, net of grants from outside parties	$ 6,814	$ 4,726	$ 17,187		$ 13,189
MIRA [Member]
Segment Reporting Information [Line Items]
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners	48.90%		48.90%