Consolidated Statement of Stockholders Equity (USD $) In Thousands	Total	Common Stock [Member]	Retained Earnings [Member]	Noncontrolling Interest [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Stockholders' Equity, Total [Member]
Stockholders' Equity at Jan. 31, 2010		$ 662,595	$ (48,742)	$ 0	$ 26,164	$ 640,017
Common stock, shares outstanding at Jan. 31, 2010		100,478
Net Income (Loss) Attributable to Parent	28,584		28,584			28,584
Net Income (Loss) Attributable to Noncontrolling Interest	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	5,529				5,529	5,529
Stock Issued During Period, Shares, Acquisitions		5,621
Stock Issued During Period, Value, Acquisitions		54,028				54,028
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition		21,026				21,026
Change in pension liability	2,349
Change in Accumulated Translation Adjustment Attributable to Noncontrolling Interest	0
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	34,113
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		5,150
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures		27,530				27,530
Stockholders' Equity at Jan. 31, 2011		765,179	(20,158)	0	31,693	776,714
Common stock, shares outstanding at Jan. 31, 2011		111,249
Net Income (Loss) Attributable to Parent	83,872		83,872			83,872
Net Income (Loss) Attributable to Noncontrolling Interest	(485)			(485)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(3,013)				(3,013)	(3,013)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition		21,003				21,003
Change in pension liability	212
Change in Accumulated Translation Adjustment Attributable to Noncontrolling Interest	(127)			(127)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	80,859
Adjustments to Additional Paid in Capital, Equity Component of Convertible Debt		42,531				42,531
Acquisition of controlling interest		(815)		8,196		(815)
Noncontrolling Interest, Change in Redemption Value	(1,682)		(1,682)	1,682		(1,682)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		4,902
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures		37,459				37,459
Stock Repurchased During Period, Shares		(6,805)
Stock Repurchased During Period, Value		(89,995)				(89,995)
Stockholders' Equity at Jan. 31, 2012		775,362	62,032	9,266	28,680	866,074
Common stock, shares outstanding at Jan. 31, 2012	109,346	109,346
Net Income (Loss) Attributable to Parent	138,736		138,736			138,736
Net Income (Loss) Attributable to Noncontrolling Interest	(102)			(102)
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	(3,281)				(3,281)	(3,281)
Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition		22,432				22,432
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation		266				266
Change in pension liability	(420)
Change in Accumulated Translation Adjustment Attributable to Noncontrolling Interest	(56)			(56)
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	135,455
Noncontrolling Interest, Change in Redemption Value			(3,590)	3,590		(3,590)
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures		5,801
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures		46,756				46,756
Stock Repurchased During Period, Shares		(2,245)
Stock Repurchased During Period, Value		(33,914)				(33,914)
Stockholders' Equity at Jan. 31, 2013		$ 810,902	$ 197,178	$ 12,698	$ 25,399	$ 1,033,479
Common stock, shares outstanding at Jan. 31, 2013	112,902	112,902