Acquisitions (Details Textual) (International Mining Machinery Holdings Ltd.) Share data in Millions, except Per Share data, unless otherwise specified	0 Months Ended		3 Months Ended	6 Months Ended		7 Months Ended	12 Months Ended		18 Months Ended
	Dec. 29, 2011 USD ($)	Dec. 29, 2011 HKD	Apr. 26, 2013 USD ($)	Dec. 29, 2011 USD ($)	Dec. 29, 2011 HKD	Feb. 10, 2012	Oct. 26, 2012 USD ($)	Jul. 25, 2012 USD ($)	Jan. 25, 2013 USD ($)	Apr. 27, 2012 USD ($)
Acquisitions (Textual) [Abstract]
Effective date of acquisition	Dec. 29, 2011	Dec. 29, 2011
Number of shares purchased	534.8	534.8
Outstanding common stock acquired	41.10%	41.10%		41.10%	41.10%
Per share price of shares purchased for acquisition		8.50			8.50
Number of shares purchased, value	$ 584,600,000			$ 584,600,000				$ 16,200,000
Subsidiary or equity method investee, cumulative percentage ownership after all transactions				69.20%	69.20%	98.90%		100.00%
Gain on preexisting interest										19,400,000
Other intangible assets and goodwill	1,160,211,000			1,160,211,000
Acquired indefinite-lived intangible assets	72,500,000			72,500,000
Finite-lived intangible assets acquired as part of business combination	80,000,000			80,000,000
Weighted-average useful life, in years	13 years 9 months 18 days	13 years 9 months 18 days
Acquisition cost			$ 300,000				$ 15,600,000		$ 24,500,000