General - Schedule of Error Corrections and Prior Period Adjustments (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended							6 Months Ended				9 Months Ended	12 Months Ended
	Jun. 30, 2015		Mar. 31, 2015	Sep. 30, 2014	Jun. 30, 2014		Mar. 31, 2014	Jun. 30, 2015		Jun. 30, 2014		Sep. 30, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Statement [Abstract]
Cost of lease and rental	$ 531,308		$ 518,422	$ 522,202	$ 507,620		$ 492,572	$ 1,049,730		$ 1,000,192		$ 1,522,394	$ 2,036,881	$ 1,925,546	$ 1,900,424
Interest expense	39,075		36,802	36,681	35,729		35,538	75,877		71,267		107,948	144,739	140,463	143,305
Earnings from continuing operations before income taxes	133,447		84,177	129,608	120,089		75,046	217,624		195,135		324,743	338,267	369,014	302,768
Provision for income taxes	47,530			45,713	44,368			78,381		70,288		116,001	118,042	125,739	102,100
Earnings from continuing operations	85,917		53,326	83,895	75,721		49,126	139,243		124,847		208,742	220,225	243,275	200,668
Net earnings	$ 85,159		52,789	83,617	$ 75,385		48,260	$ 137,948		$ 123,645		207,262	$ 218,341	$ 237,871	$ 209,748
Earnings (loss) per common share — Diluted, Net Earnings	$ 1.59	[1]			$ 1.41	[1]		$ 2.59	[1]	$ 2.32	[1]		$ 4.14	$ 4.63	$ 3.90
Statement of Comprehensive Income [Abstract]
Comprehensive income (loss)	$ 111,333		100	39,700	$ 102,603		36,800	$ 111,360		$ 139,398		179,100	$ 36,400	$ 387,300	$ 189,300
Statement of Financial Position [Abstract]
Revenue earning equipment, net	7,854,037		7,409,529					7,854,037					7,201,886	6,592,826
Total assets	10,638,264		10,107,975					10,638,264					9,883,424	9,205,771
Short-term debt and current portion of long-term debt	347,817		35,452					347,817					36,284	272,203
Accrued expenses and other current liabilities	523,722		482,521					523,722					513,679	494,395
Total current liabilities	1,523,732		1,143,446					1,523,732					1,110,815	1,241,962
Long-term debt	4,869,208		4,880,638					4,869,208					4,694,335	4,022,975
Other non-current liabilities	799,415		784,948					799,415					783,342	614,713
Deferred income taxes	1,532,470		1,487,913					1,532,470					1,475,845	1,429,560
Total liabilities	8,724,825		8,296,944					8,724,825					8,064,337	7,309,210
Retained earnings	1,544,047		1,478,660					1,544,047					1,450,509	1,390,603
Total shareholders’ equity	1,913,439		1,811,031					1,913,439					1,819,087	1,896,561
Total liabilities and shareholders’ equity	10,638,264		10,107,975					10,638,264					9,883,424	9,205,771
Statement of Cash Flows [Abstract]
Net earnings	$ 85,159		52,789	83,617	75,385		48,260	137,948		123,645		207,262	218,341	237,871	209,748
Depreciation expense			268,649				251,871	546,699		512,109		781,367	1,057,813	983,610	962,052
Deferred income tax expense			26,646				21,667	67,592		59,987			104,713	113,621	86,984
Accrued expenses and other non-current liabilities			(21,576)				(32,999)	17,005		(67,439)		(46,357)	(53,109)	(64,423)	(64,242)
Net cash provided by operating activities from continuing operations			283,845				237,660	658,698		542,888		981,044	1,382,818	1,251,811	1,160,175
Debt proceeds								930,090		765,713		895,733	965,533	556,989	875,961
Debt repaid, including capital and financing lease obligations			(463,536)				(252,845)	(486,103)		(277,636)		(284,811)	(293,488)	(379,189)	(309,988)
Net cash provided by financing activities from continuing operations			178,870				215,169	445,520		423,565		332,501	311,650	347,070	437,938
Purchases of property and revenue earning equipment								(1,329,218)		(1,255,222)			(2,259,164)	(2,122,628)	(2,133,235)
Sale and leaseback of revenue earning equipment										0		0	0	0	0
Net cash used in investing activities from continuing operations								$ (1,078,663)		(939,818)		(1,297,281)	(1,704,510)	(1,603,818)	(1,634,457)
As Previously Reported [Member]
Income Statement [Abstract]
Cost of lease and rental			519,174	522,888	508,091		493,043			1,001,134		1,524,022	2,039,263	1,928,933	1,902,823
Interest expense			35,849	35,882	35,302		35,109			70,411		106,293	142,075	137,196	140,557
Earnings from continuing operations before income taxes			84,378	129,721	120,045		75,004			195,049		324,770	338,549	368,895	303,117
Provision for income taxes				45,754								116,011	118,090	125,699	102,218
Earnings from continuing operations			53,453	83,967			49,098					208,759	220,459	243,196	200,899
Net earnings			52,916	83,689			48,232			123,590		207,279	$ 218,575	$ 237,792	$ 209,979
Earnings (loss) per common share — Diluted, Net Earnings													$ 4.14	$ 4.63	$ 3.91
Statement of Comprehensive Income [Abstract]
Comprehensive income (loss)			154	39,761	102,576		36,767			139,343		179,104	$ 36,553	$ 387,163	$ 189,525
Statement of Financial Position [Abstract]
Revenue earning equipment, net			7,208,345										6,994,448	6,490,837
Total assets			9,906,791										9,675,986	9,103,782
Short-term debt and current portion of long-term debt			11,417										12,207	259,438
Accrued expenses and other current liabilities			489,647										520,532	496,337
Total current liabilities			1,126,537										1,093,591	1,231,139
Long-term debt			4,692,503										4,500,275	3,929,987
Other non-current liabilities			788,094										786,676	616,305
Deferred income taxes			1,488,111										1,475,970	1,429,637
Total liabilities			8,095,245										7,856,512	7,207,068
Retained earnings			1,479,175										1,450,896	1,390,756
Total shareholders’ equity			1,811,546										1,819,474	1,896,714
Total liabilities and shareholders’ equity			9,906,791										9,675,986	9,103,782
Statement of Cash Flows [Abstract]
Net earnings			52,916	83,689			48,232			123,590		207,279	218,575	237,792	209,979
Depreciation expense			262,395				248,815			505,997		770,067	1,040,259	957,141	939,677
Deferred income tax expense			26,719				21,653						104,761	113,581	87,102
Accrued expenses and other non-current liabilities			(21,490)				(29,901)			(67,629)		(41,471)	(48,664)	(66,564)	(68,267)
Net cash provided by operating activities from continuing operations			277,878				237,660			536,500		974,656	1,369,991	1,223,082	1,134,124
Debt proceeds										765,713		769,908	839,708	556,989	745,777
Debt repaid, including capital and financing lease obligations			(457,569)				(252,845)			(271,248)		(278,423)	(280,661)	(332,624)	(283,937)
Net cash provided by financing activities from continuing operations			184,837				215,169			429,953		213,064	198,652	393,635	333,805
Purchases of property and revenue earning equipment													(2,259,164)	(2,140,464)	(2,133,235)
Sale and leaseback of revenue earning equipment										0		125,825	125,825	0	130,184
Net cash used in investing activities from continuing operations										(939,818)		(1,171,456)	(1,578,685)	(1,621,654)	(1,504,273)
Adjustment [Member]
Income Statement [Abstract]
Cost of lease and rental			(800)	(700)	(500)		(400)			(900)		(1,600)	(2,400)	(3,400)	(2,400)
Interest expense			1,000	800	400		400			900		1,600	2,600	3,300	2,700
Earnings from continuing operations before income taxes			(200)	(100)	100		0			100		(100)	(200)	100	(300)
Provision for income taxes				(100)								0	(100)	0	(100)
Earnings from continuing operations			(200)	(100)			0					(100)	(300)	100	(200)
Net earnings			(100)	(100)			100			0		0	$ (300)	$ 100	$ (300)
Earnings (loss) per common share — Diluted, Net Earnings													$ 0.00	$ 0.00	$ (0.01)
Statement of Comprehensive Income [Abstract]
Comprehensive income (loss)			(127)	(72)	$ 27		28			55		(17)	$ (234)	$ 79	$ (231)
Statement of Financial Position [Abstract]
Revenue earning equipment, net			201,200										207,438	102,000
Total assets			201,200										207,400	102,000
Short-term debt and current portion of long-term debt			24,100										24,100	12,800
Accrued expenses and other current liabilities			(7,100)										(6,800)	(1,900)
Total current liabilities			16,900										17,200	10,900
Long-term debt			188,100										194,000	93,000
Other non-current liabilities			(3,200)										(3,400)	(1,600)
Deferred income taxes			(200)										(200)	0
Total liabilities			201,700										207,800	102,100
Retained earnings			(500)										(400)	(200)
Total shareholders’ equity			(500)										(400)	(100)
Total liabilities and shareholders’ equity			201,200										207,400	102,000
Statement of Cash Flows [Abstract]
Net earnings			(100)	$ (100)			100			0		0	(300)	100	(300)
Depreciation expense			6,200				3,100			6,100		11,300	17,554	26,500	22,400
Deferred income tax expense			(100)				0						(48)	0	(100)
Accrued expenses and other non-current liabilities			(100)				(3,100)			200		(4,900)	(4,400)	2,200	4,100
Net cash provided by operating activities from continuing operations			5,967				0			6,400		0	12,800	28,700	26,100
Debt proceeds										0		125,800	125,800	0	130,200
Debt repaid, including capital and financing lease obligations			(5,967)				0			(6,400)		(6,400)	(12,800)	(46,600)	(26,100)
Net cash provided by financing activities from continuing operations			$ (5,967)				$ 0			(6,400)		119,400	113,000	(46,500)	104,100
Purchases of property and revenue earning equipment													0	17,900	0
Sale and leaseback of revenue earning equipment										0		(125,800)	(125,800)	0	(130,200)
Net cash used in investing activities from continuing operations										$ 0		$ (125,800)	$ (125,800)	$ 17,900	$ (130,200)

[1] EPS amounts may not be additive due to rounding.