Stock-Based Compensation - Nonvested Stock Award Activity (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
		Jul. 31, 2017	Jul. 31, 2016	Jul. 31, 2015
Number of Shares
Nonvested stock awards at the beginning of the period (in shares)		331,367,000	343,519,000	525,842,000
Granted (in shares)		113,065,000	175,700,000	144,278,000
Vested (in shares)	[1]	(216,212,000)	(183,045,000)	(313,797,000)
Forfeited (in shares)		(5,922,000)	(4,807,000)	(12,804,000)
Nonvested stock awards at the end of the period (in shares)		222,298,000	331,367,000	343,519,000
Weighted Average Fair Value
Nonvested stock awards at the beginning of the period (in dollars per share)		$ 46.09	$ 32.77	$ 22.25
Granted (in dollars per share)		81.77	55.40	39.77
Vested (in dollars per share)	[1]	43.62	30.06	18.62
Forfeited (in dollars per share)		59.40	45.06	26.20
Nonvested stock awards at the end of the period (in dollars per share)		$ 66.28	$ 46.09	$ 32.77
Aggregate fair value, vested in period		$ 9,431	$ 5,503	$ 5,844
Number of Time-based Shares
Number of Shares
Nonvested stock awards at the beginning of the period (in shares)		331,367,000	343,519,000	525,842,000
Granted (in shares)		86,305,000	175,700,000	144,278,000
Vested (in shares)	[1]	(214,932,000)	(183,045,000)	(313,797,000)
Forfeited (in shares)		(5,922,000)	(4,807,000)	(12,804,000)
Nonvested stock awards at the end of the period (in shares)		196,818,000	331,367,000	343,519,000
Number of Performance-based Shares
Number of Shares
Granted (in shares)		16,960,000
Vested (in shares)	[1]	(725,000)
Nonvested stock awards at the end of the period (in shares)		16,235,000
Number of Market-based Shares
Number of Shares
Granted (in shares)		9,800,000
Vested (in shares)	[1]	(555,000)
Nonvested stock awards at the end of the period (in shares)		9,245,000

[1] The aggregate fair value of all nonvested stock awards which vested was approximately $9,431, $5,503 and $5,844 in fiscal 2017, 2016 and 2015, respectively.