Consolidated Condensed Statements of Earnings (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Lease and rental revenues	$ 797,014	$ 798,387	$ 1,564,604	$ 1,566,141
Services revenue	871,027	785,791	1,722,894	1,544,918
Fuel services revenue	125,173	119,566	253,879	222,357
Total revenues	1,793,214	1,703,744	3,541,377	3,333,416
Cost of lease and rental	578,389	555,302	1,157,151	1,107,792
Cost of services	734,764	646,129	1,448,844	1,277,843
Cost of fuel services	121,604	115,478	247,454	214,379
Other operating expenses	27,406	27,796	58,677	57,947
Selling, general and administrative expenses	201,626	207,028	403,387	411,431
Non-operating pension costs	6,587	15,420	13,917	22,230
Used vehicle sales, net	15,322	(12,000)	14,542	(31,129)
Interest expense	34,852	37,268	69,738	75,157
Miscellaneous income, net	(8,028)	(5,456)	(12,981)	(7,721)
Total expenses	1,712,522	1,586,965	3,400,729	3,127,929
Earnings from continuing operations before income taxes	80,692	116,779	140,648	205,487
Provision for income taxes	29,349	42,737	51,026	75,260
Earnings from continuing operations	51,343	74,042	89,622	130,227
Loss from discontinued operations, net of tax	(527)	(292)	(657)	(683)
Net earnings	$ 50,816	$ 73,750	$ 88,965	$ 129,544
Earnings (loss) per common share — Basic
Continuing operations (in dollars per share)	$ 0.97	$ 1.39	$ 1.69	$ 2.45
Discontinued operations (in dollars per share)	(0.01)	(0.01)	(0.01)	(0.01)
Net earnings (in dollars per share)	0.96	1.39	1.68	2.43
Earnings (loss) per common share — Diluted
Continuing operations (in dollars per share)	0.97	1.38	1.68	2.43
Discontinued operations (in dollars per share)	(0.01)	(0.01)	(0.01)	(0.01)
Net earnings (in dollars per share)	0.96	1.38	1.67	2.42
Cash dividends declared per common share (in dollars per share)	$ 0.44	$ 0.41	$ 0.88	$ 0.82