ACQUISITIONS, DISCONTINUED OPERATIONS AND FORMATION OF SHANGHAI ELECTRIC JV (Details 2)	3 Months Ended		6 Months Ended				3 Months Ended										6 Months Ended	3 Months Ended		6 Months Ended		0 Months Ended	1 Months Ended		3 Months Ended
	Jun. 29, 2013 USD ($)	Jun. 30, 2012 USD ($)	Jun. 29, 2013 USD ($)	Jun. 30, 2012 USD ($)	Jun. 29, 2013 Shanghai Electric JV	Dec. 30, 2011 Shanghai Electric JV	Jun. 29, 2013 Dielectric USD ($)	Jun. 29, 2013 Dielectric Maximum USD ($)	Mar. 30, 2013 Kayex USD ($)	Dec. 31, 2012 Tianyu USD ($)	Dec. 31, 2012 Tianyu CNY	Jun. 29, 2013 Weil McLain Shandong USD ($)	Mar. 30, 2013 Weil McLain Shandong USD ($)	Dec. 31, 2012 Weil McLain Shandong USD ($)	Jun. 29, 2013 SPX Service Solutions ("Service Solutions") USD ($)	Dec. 31, 2012 SPX Service Solutions ("Service Solutions") USD ($)	Jun. 29, 2013 SPX Service Solutions ("Service Solutions") USD ($)	Jun. 29, 2013 Other businesses sold prior to the earliest date presented in the financial statements USD ($)	Jun. 30, 2012 Other businesses sold prior to the earliest date presented in the financial statements USD ($)	Jun. 29, 2013 Other businesses sold prior to the earliest date presented in the financial statements USD ($)	Jun. 30, 2012 Other businesses sold prior to the earliest date presented in the financial statements USD ($)	Dec. 30, 2011 Certain assets of dry cooling products business Shanghai Electric JV CNY	Dec. 31, 2012 Certain assets of dry cooling products business Shanghai Electric JV CNY	Jan. 31, 2012 Certain assets of dry cooling products business Shanghai Electric JV CNY	Mar. 31, 2012 Certain assets of dry cooling products business Shanghai Electric JV USD ($)
Discontinued Operations
Gain (loss) on disposition of discontinued operations, net of tax	$ 2,700,000	$ (600,000)	$ (2,500,000)	$ (900,000)				$ 100,000	$ (2,100,000)	$ (1,800,000)				$ 2,200,000		$ 313,400,000
Cash consideration, exclusive of cash transferred							4,700,000				1			2,700,000
Cash consideration, gross																1,134,900,000							25,800,000	51,500,000
Cash transferred with discontinued business										1,100,000				3,100,000
Adjustment to gain (loss) on sale of discontinued operations, net of tax													(400,000)		3,000,000		1,600,000	(300,000)	(600,000)	(1,600,000)	(900,000)
Working capital settlement												1,100,000
Income (loss) from discontinued operations and related income taxes
Income (loss) from discontinued operations	(1,900,000)	16,800,000	(9,200,000)	23,000,000
Income tax (provision) benefit	3,800,000	(6,500,000)	2,900,000	(8,700,000)
Income (loss) from discontinued operations, net of tax	1,900,000	10,300,000	(6,300,000)	14,300,000
Results of operations for businesses reported as discontinued operations
Revenues	1,400,000	263,200,000	6,700,000	503,600,000
Pre-tax income (loss)	(1,400,000)	18,000,000	(6,200,000)	24,700,000
Other information
Interest acquired in joint venture (as a percent)					45.00%	45.00%
Dispositions, consideration to be received																						96,700,000
Net gain associated with deconsolidation				$ 20,500,000																					$ 20,500,000