Consolidated Statement Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Oct. 31, 2017	Oct. 31, 2016
Cash flows from operating activities:
Cash received from customers	$ 30,645,389	$ 21,076,446
Cash paid to vendors and employees	(30,031,181)	(20,776,017)
Interest paid, net	(73,180)	(18,982)
Income taxes paid	(100,615)	(69,960)
Net cash provided by operating activities	440,413	211,487
Cash flows from investing activities:
Acquisition of businesses, net of cash acquired	(2,249,642)	(2,685)
Expenditures for property and equipment	(179,114)	(18,785)
Software and software development costs	(34,865)	(12,118)
Net cash used in investing activities	(2,463,621)	(33,588)
Cash flows from financing activities:
Borrowings on long-term debt	1,008,148	0
Principal payments on long-term debt	(565,952)	0
Cash paid for debt issuance costs	(5,871)	(14,988)
Net repayments on revolving credit loans	(24,851)	(1,476)
Payments for employee tax withholdings on equity awards	(5,915)	(4,385)
Proceeds from the reissuance of treasury stock	1,079	492
Net cash provided by (used in) financing activities	406,638	(20,357)
Effect of exchange rate changes on cash and cash equivalents	53,624	2,854
Net (decrease) increase in cash and cash equivalents	(1,562,946)	160,396
Cash and cash equivalents at beginning of year	2,125,591	531,169
Cash and cash equivalents at end of period	562,645	691,565
Reconciliation of net income to net cash provided by operating activities:
Net income	115,381	116,273
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	112,907	41,223
Provision for losses on accounts receivable	13,191	3,457
Stock-based compensation expense	21,217	11,020
Accretion of debt discount and debt issuance costs	1,692	626
Changes in operating assets and liabilities, net of acquisitions:
Accounts receivable	207,945	91,938
Inventories	(415,623)	(148,116)
Prepaid expenses and other assets	12,071	57,178
Accounts payable	471,819	109,404
Accrued expenses and other liabilities	(100,187)	(71,516)
Total adjustments	325,032	95,214
Net cash provided by operating activities	440,413	211,487
Supplemental schedule of non-cash investing activities:
Issuance of stock to acquire business	$ 247,232	$ 0