Business Combinations (Narrative) (Details) $ in Thousands	1 Months Ended			3 Months Ended		6 Months Ended
	Jul. 31, 2016 USD ($)	Apr. 30, 2016 USD ($)	Feb. 29, 2016 USD ($)	Jul. 31, 2016 USD ($)	Jul. 31, 2015 USD ($)	Jul. 31, 2016 USD ($) company	Jul. 31, 2015 USD ($)	Jan. 31, 2016 USD ($)
Business Acquisition [Line Items]
Business combinations, net of cash acquired				$ 2,798,194	$ 18,451	$ 2,799,993	$ 30,921
SteelBrick, Inc.
Business Acquisition [Line Items]
Investment owned								$ 13,900
Demandware
Business Acquisition [Line Items]
Consideration transferred	$ 2,929,680
Liabilities incurred	$ 500,000
Share conversion ratio	0.9545
Equity interest issued or issuable	$ 135,200			135,200		135,200
Fair value of stock options and restricted stock awards assumed	9,344
Allocated to future services	125,900			125,900		125,900
Goodwill acquired						1,884,886
Intangible assets remaining to be amortized	788,400			788,400		788,400
Amortization of acquired intangible assets				11,900
Amortization expense, remainder of fiscal year	72,300			72,300		72,300
Amortization expense, 2018	137,700			137,700		137,700
Amortization expense, 2019	132,400			132,400		132,400
Amortization expense, 2020	131,100			131,100		131,100
Amortization expense, 2021	130,300			$ 130,300		130,300
Demandware | General and administrative
Business Acquisition [Line Items]
Acquisition costs	$ 15,500
SteelBrick, Inc.
Business Acquisition [Line Items]
Consideration transferred			$ 314,785
Percentage of acquired platform delivered on parent company platform			100.00%
Share conversion ratio			0.08
Fair value of equity interest in acquiree			$ 23,726
Equity interest in acquiree			6.00%
Remeasurement gain			$ 9,800
Equity interest issued or issuable			39,600
Fair value of stock options and restricted stock awards assumed			10,989
Allocated to future services			$ 28,600
Goodwill acquired						217,986
MetaMind
Business Acquisition [Line Items]
Equity interest issued or issuable		$ 5,500
Fair value of stock options and restricted stock awards assumed		500
Allocated to future services		5,000
Business combinations, net of cash acquired		32,800
Goodwill acquired		31,200				$ 31,242
MetaMind | CEO and Chairman of MetaMind
Business Acquisition [Line Items]
Consideration transferred		$ 6,000
Ownership percentage (greater than 10%)		10.00%
Other Business Combination
Business Acquisition [Line Items]
Number of businesses acquired | company						3
Business combinations, net of cash acquired						$ 58,400
Goodwill acquired						$ 45,907