Notes Payable and Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands		1 Months Ended	12 Months Ended
	Jun. 30, 2016	Sep. 30, 2015	Aug. 31, 2017	Aug. 31, 2018	May 31, 2018	Feb. 28, 2018	Nov. 30, 2017	May 31, 2017	Feb. 28, 2017	Nov. 30, 2016
Debt Instrument [Line Items]
Notes payable			$ 1,985,163	$ 2,272,196	$ 2,868,506	$ 3,071,639	$ 2,480,264	$ 3,321,808	$ 3,867,438	$ 3,227,564
Total long-term debt				1,918,689
Debt Issuance Costs, Net			(4,820)	(4,179)
Capital Lease Obligations			33,075	25,280
Long-term Debt, Fair Value			2,179,793	1,930,255
Less current portion			156,345	167,565	53,056	46,290	71,022	193,096	205,136	206,894
Long-term portion			2,023,448	$ 1,762,690	$ 1,905,515	$ 1,915,843	$ 1,936,744	$ 2,046,264	$ 2,051,567	$ 1,958,907
Unsecured debt | Minimum
Debt Instrument [Line Items]
Interest rate				1.30%
Unsecured debt | Maximum
Debt Instrument [Line Items]
Interest rate				15.25%
Term loans from cooperative and other banks, due in installments through 2018 | Line of credit | Revolving credit facility
Debt Instrument [Line Items]
Interest rate				5.59%
Total long-term debt			15,000	$ 0
Committed Term Loans, September 2015 [Member] | Secured debt
Debt Instrument [Line Items]
Total long-term debt				236,000
Debt Instrument, Face Amount				600,000
Debt Instrument, Term		10 years
Notes Payable, Other Payables [Member] | Notes Payable, Other Payables [Member] | Revolving credit facility
Debt Instrument [Line Items]
Notes payable			1,695,423	$ 1,437,264
Private placement, payable in equal installments beginning in 2014 through 2018 | Unsecured debt
Debt Instrument [Line Items]
Interest rate				6.18%
Total long-term debt			80,000	$ 0
Debt Instrument, Face Amount				$ 400,000
Private placement, payable in installments through 2018 | Unsecured debt
Debt Instrument [Line Items]
Interest rate				5.60%
Total long-term debt			4,615	$ 0
Debt Instrument, Face Amount				60,000
Private placement, payable in equal installments beginning in 2014 through 2018 | Unsecured debt
Debt Instrument [Line Items]
Total long-term debt			10,000	$ 0
Private placement, payable in equal installments beginning in 2014 through 2018 | Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Interest rate				5.78%
Debt Instrument, Face Amount				$ 50,000
Private placement, payable in equal installments beginning in 2017 through 2021 | Unsecured debt
Debt Instrument [Line Items]
Total long-term debt			80,000	$ 60,000
Private placement, payable in equal installments beginning in 2017 through 2021 | Notes Payable, Other Payables [Member]
Debt Instrument [Line Items]
Interest rate				4.00%
Debt Instrument, Face Amount				$ 100,000
Private placement, payable in its entirety in 2019 | Unsecured debt
Debt Instrument [Line Items]
Interest rate				4.08%
Total long-term debt			130,690	$ 129,229
Debt Instrument, Face Amount				$ 130,000
Private placement, payable in its entirety in 2021 | Unsecured debt
Debt Instrument [Line Items]
Interest rate				4.52%
Total long-term debt			163,496	$ 157,528
Debt Instrument, Face Amount				$ 160,000
Private placement, payable in its entirety in 2023 | Unsecured debt
Debt Instrument [Line Items]
Interest rate				4.67%
Total long-term debt			135,792	$ 128,577
Debt Instrument, Face Amount				$ 130,000
Private placement, payable in 2023 152k [Member] [Member] | Unsecured debt
Debt Instrument [Line Items]
Interest rate				4.39%
Total long-term debt			152,000	$ 152,000
Debt Instrument, Face Amount				$ 152,000
Private placement, payable in 2025 80k [Member] | Unsecured debt
Debt Instrument [Line Items]
Interest rate				3.85%
Total long-term debt			80,000	$ 80,000
Debt Instrument, Face Amount				$ 80,000
Private placement, payable in 2025 100k [Member] | Unsecured debt
Debt Instrument [Line Items]
Interest rate				3.80%
Total long-term debt			100,000	$ 100,000
Debt Instrument, Face Amount				$ 100,000
Private placement, payable in 2025 150k [Member] [Member] | Unsecured debt
Debt Instrument [Line Items]
Interest rate				4.58%
Total long-term debt			149,293	$ 145,213
Debt Instrument, Face Amount				$ 150,000
Private placement, payable in its entirety in 2026 | Unsecured debt
Debt Instrument [Line Items]
Interest rate				4.82%
Total long-term debt			80,000	$ 80,000
Debt Instrument, Face Amount				$ 80,000
Private placement, payable in its entirety in 2027 [Member] | Unsecured debt
Debt Instrument [Line Items]
Interest rate				4.69%
Total long-term debt			58,000	$ 58,000
Debt Instrument, Face Amount				$ 58,000
Private placement, payable in its entirety in 2028 [Member] | Unsecured debt
Debt Instrument [Line Items]
Interest rate				4.74%
Total long-term debt			95,000	$ 95,000
Debt Instrument, Face Amount				$ 95,000
Private placement, payable in its entirety in 2031 [Member] | Unsecured debt
Debt Instrument [Line Items]
Interest rate				4.89%
Total long-term debt			100,000	$ 100,000
Debt Instrument, Face Amount				$ 100,000
Private placement, payable in its entirety 2033 [Member] | Unsecured debt
Debt Instrument [Line Items]
Interest rate				4.71%
Total long-term debt			100,000	$ 100,000
Debt Instrument, Face Amount				$ 100,000
Private placement, payable in its entirety in 2036 [Member] | Unsecured debt
Debt Instrument [Line Items]
Interest rate				5.40%
Total long-term debt			125,000	$ 125,000
Debt Instrument, Face Amount				125,000
Private Placement [Member]
Debt Instrument [Line Items]
Total long-term debt			1,643,886	$ 1,510,547
Term loans, 430K payable in 2025 [Member] | Unsecured debt
Debt Instrument [Line Items]
Interest rate				2.25%
Total long-term debt			430,000	$ 366,000
Bank financing [Member]
Debt Instrument [Line Items]
Total long-term debt			445,000	366,000
Other notes and contracts | Secured debt
Debt Instrument [Line Items]
Total long-term debt			62,652	32,607
Committed Term Loans, September 2016 [Member] | Secured debt
Debt Instrument [Line Items]
Total long-term debt				$ 130,000
Debt instrument, amount available to be paid and re-advanced	$ 300,000
Amount re-advanced			$ 130,000
Debt Instrument, Face Amount	$ 600,000
Debt Instrument, Term	10 years