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Business and Summary of Significant Accounting Policies \| Recently Adopted Accounting Standards (Details) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 31, 2019	Oct. 31, 2018	Jul. 31, 2018	Apr. 30, 2018	Jan. 31, 2018	Oct. 31, 2017	Jul. 31, 2017	Apr. 30, 2017	Jan. 31, 2019	Jan. 31, 2018	Jan. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues	$ 10,464,501	$ 9,340,029	$ 8,886,101	$ 8,548,319	$ 10,033,397	$ 8,448,471	$ 8,092,353	$ 7,023,620	$ 37,238,950	$ 33,597,841	$ 24,193,697
Accounts Receivable, Net, Current	6,241,740				6,035,716				6,241,740	6,035,716
Inventories	3,297,385				2,965,521				3,297,385	2,965,521
Prepaid expenses and other assets	354,601				403,548				354,601	403,548
Accounts Payable, Current	7,496,466				6,962,193				7,496,466	6,962,193
Accrued Liabilities, Current	$ 1,000,126				1,169,986				1,000,126	1,169,986
Cost of Goods and Services Sold					9,416,536	7,922,390	7,576,762	6,566,532	$ 34,983,051	31,482,220	22,891,770
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] \| Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues										(3,177,170)	(2,041,179)
Accounts Receivable, Net, Current					252,050					252,050
Inventories					(99,697)					(99,697)
Prepaid expenses and other assets					115,370					115,370
Accounts Payable, Current					14,911					14,911
Accrued Liabilities, Current					252,812					252,812
Cost of Goods and Services Sold										(3,177,170)	(2,041,179)
Calculated under Revenue Guidance in Effect before Topic 606 [Member] \| Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Revenues					11,092,529	9,135,728	8,882,691	7,664,063		36,775,011	26,234,876
Accounts Receivable, Net, Current					5,783,666					5,783,666
Inventories					3,065,218					3,065,218
Prepaid expenses and other assets					288,178					288,178
Accounts Payable, Current					6,947,282					6,947,282
Accrued Liabilities, Current					917,174					917,174
Cost of Goods and Services Sold					$ 10,475,668	$ 8,609,647	$ 8,367,100	$ 7,206,975		$ 34,659,390	$ 24,932,949