Segment and Geographic Area Information Geographic Area Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating Revenues	$ 2,348,550	$ 2,208,044	$ 2,001,527
Percent of total operating revenues	100.00%	100.00%	100.00%
Property and equipment, net	$ 4,613,014	$ 4,656,921
Percent of total property and equipment	100.00%	100.00%
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating Revenues	$ 1,249,095	$ 1,176,674	$ 1,142,141
Percent of total operating revenues	53.20%	53.30%	57.10%
Property and equipment, net	$ 3,449,739	$ 3,404,204
Percent of total property and equipment	74.80%	73.10%
Australia [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating Revenues	$ 301,678	$ 307,510	$ 222,586
Percent of total operating revenues	12.80%	13.90%	11.10%
Property and equipment, net	$ 609,450	$ 664,367
Percent of total property and equipment	13.10%	14.30%
Canada [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating Revenues	$ 109,775	$ 97,611	$ 94,623
Percent of total operating revenues	4.70%	4.40%	4.70%
Property and equipment, net	$ 229,540	$ 253,597
Percent of total property and equipment	5.00%	5.40%
U.K. [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating Revenues	$ 555,563	$ 475,239	$ 378,551
Percent of total operating revenues	23.70%	21.50%	18.90%
Property and equipment, net	$ 307,888	$ 317,495
Percent of total property and equipment	6.70%	6.80%
Netherlands [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating Revenues	$ 47,090	$ 78,819	$ 101,837
Percent of total operating revenues	2.00%	3.60%	5.10%
Poland [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating Revenues	$ 74,294	$ 59,254	$ 46,428
Percent of total operating revenues	3.10%	2.70%	2.30%
Other [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating Revenues	$ 11,055	$ 12,937	$ 15,361
Percent of total operating revenues	0.50%	0.60%	0.80%
Property and equipment, net	$ 16,397	$ 17,258
Percent of total property and equipment	0.40%	0.40%
Non-US [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Operating Revenues	$ 1,099,455	$ 1,031,370	$ 859,386
Percent of total operating revenues	46.80%	46.70%	42.90%
Property and equipment, net	$ 1,163,275	$ 1,252,717
Percent of total property and equipment	25.20%	26.90%