The maximum period over which the fair value of restricted stock and restricted stock units are amortized.

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The historical period upon which annual expected stock price volatility is based.

+ References

No definition available.

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Represents the daily treasury yield curve period, in years, upon which the average risk-free interest rate is based.

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No definition available.

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Represents the assumed correlation between the total shareholder return for the entities stock and the S&P 500 Composite Index and the S&P Composite 1500 Industrials Index.

+ References

No definition available.

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Share Based Compensation Arrangement by Share Based Payment Award, Number of Shares Available for Grant Decrease

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No definition available.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of tax benefit for recognition of expense of award under share-based payment arrangement.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The risk-free interest rate assumption that is used in valuing an option on its own shares.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Shareholders' Equity and Long-Term Incentive Compensation - Long-Term Incentive Compensation (Details) - USD ($) $ in Millions				12 Months Ended
	Feb. 20, 2020	Feb. 21, 2019	Feb. 22, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Assumptions in determining the fair value of awards granted
Historical period upon which annual expected stock price volatility is based (years)				3 years
Minimum
Assumptions in determining the fair value of awards granted
Daily treasury yield curve period upon which average risk-free interest rate is based (years)				1 year
Maximum
Stock-based Compensation
Maximum period over which the fair value of restricted stock shares and restricted stock units are amortized				3 years
Assumptions in determining the fair value of awards granted
Daily treasury yield curve period upon which average risk-free interest rate is based (years)				3 years
2019 Stock Compensation Plan \| Maximum
Stock-based Compensation
Shares available for grant (in shares)				4,407,000
Directors' Plan \| Maximum
Stock-based Compensation
Shares available for grant (in shares)				27,000.000
PSU's, RSU's, RS's, and Stock Options
Stock-based Compensation
Compensation expense				$ 12.8	$ 10.8	$ 11.6
PSU's, RSU's, and RS's \| Minimum
Stock-based Compensation
Vesting period (years)				1 year
PSU's, RSU's, and RS's \| Maximum
Stock-based Compensation
Vesting period (years)				3 years
Restricted stock shares and restricted stock units
Stock-based Compensation
Related tax benefit				$ 2.2	$ 2.6	2.8
Restricted stock shares and restricted stock units \| 2019 Stock Compensation Plan
Stock-based Compensation
Reduction of shares available for grant (in shares)				2
Restricted stock shares and restricted stock units \| Directors' Plan
Stock-based Compensation
Vesting period (years)				1 year
PSU's
Stock-based Compensation
Vesting period (years)				3 years
Assumptions in determining the fair value of awards granted
Annual Expected Stock Price Volatility		32.70%	42.25%	29.47%
Annual Expected Dividend Yield		0.00%	0.00%	0.00%
Risk-Free Interest Rate		2.53%	2.38%	1.35%
Correlation Between Total Shareholder Return for SPX and the Applicable S&P Index		0.3875	0.3267	0.3547
PSU's \| Peer group within S&P 600 Capital Goods Index
Assumptions in determining the fair value of awards granted
Annual Expected Stock Price Volatility		34.75%	34.99%	34.93%
Risk-Free Interest Rate		2.48%	2.38%	1.35%
Long Term Cash Awards
Stock-based Compensation
Vesting period (years)					3 years
Compensation expense				$ 1.2	$ 2.8	$ 3.9
Stock options
Stock-based Compensation
Vesting period (years)	3 years
Assumptions in determining the fair value of awards granted
Annual Expected Stock Price Volatility	33.48%	32.70%	31.14%
Annual Expected Dividend Yield	0.00%	0.00%	0.00%
Risk-Free Interest Rate	1.41%	2.53%	2.75%
Historical period upon which annual expected stock price volatility is based (years)	6 years
Stock options \| Minimum
Assumptions in determining the fair value of awards granted
Daily treasury yield curve period upon which average risk-free interest rate is based (years)	5 years
Stock options \| Maximum
Assumptions in determining the fair value of awards granted
Daily treasury yield curve period upon which average risk-free interest rate is based (years)	7 years