Consolidated Condensed Statements of Earnings (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Lease and rental revenues	$ 823,197	$ 803,006	$ 2,387,801	$ 2,369,147
Services revenue	896,245	801,004	2,619,139	2,345,922
Fuel services revenue	129,087	120,408	382,966	342,765
Total revenues	1,848,529	1,724,418	5,389,906	5,057,834
Cost of lease and rental	588,626	557,901	1,745,777	1,665,693
Cost of services	761,470	658,793	2,210,314	1,936,636
Cost of fuel services	124,562	116,904	372,016	331,283
Other operating expenses	28,445	27,997	87,122	85,944
Selling, general and administrative expenses	216,653	191,337	620,041	602,768
Non-operating pension costs	6,958	7,468	20,875	29,698
Used vehicle sales, net	(2,727)	(1,873)	11,815	(33,002)
Interest expense	34,854	37,440	104,591	112,597
Miscellaneous income, net	(4,655)	(3,247)	(17,636)	(10,968)
Total expenses	1,754,186	1,592,720	5,154,915	4,720,649
Earnings from continuing operations before income taxes	94,343	131,698	234,991	337,185
Provision for income taxes	35,430	46,560	86,456	121,820
Earnings from continuing operations	58,913	85,138	148,535	215,365
Loss from discontinued operations, net of tax	(290)	(386)	(947)	(1,069)
Net earnings	$ 58,623	$ 84,752	$ 147,588	$ 214,296
Earnings (loss) per common share — Basic
Continuing operations (in dollars per share)	$ 1.12	$ 1.60	$ 2.81	$ 4.05
Discontinued operations (in dollars per share)	(0.01)	(0.01)	(0.02)	(0.02)
Net earnings (in dollars per share)	1.11	1.60	2.79	4.03
Earnings (loss) per common share — Diluted
Continuing operations (in dollars per share)	1.11	1.59	2.79	4.02
Discontinued operations (in dollars per share)	(0.01)	(0.01)	(0.02)	(0.02)
Net earnings (in dollars per share)	1.11	1.59	2.77	4.00
Cash dividends declared per common share (in dollars per share)	$ 0.46	$ 0.44	$ 1.34	$ 1.26