Business Acquistiions - Narrative (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended			3 Months Ended
	Dec. 31, 2014 Acquisition	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014
Business Acquisition [Line Items]
Number of acquisitions completed	7
Acquisition of businesses, net of cash acquired	$ 183.8	$ 96.5	$ 90.7
Goodwill	874.7	800.4	755.5	874.7
RFL Electronics
Business Acquisition [Line Items]
Acquisition of businesses, net of cash acquired				20.0
Intangible assets	5.3			5.3
Weighted average useful life				15 years
Goodwill expected to be deductible for tax purposes	0			0
Goodwill	7.3			7.3
RigPower, LLC
Business Acquisition [Line Items]
Acquisition of businesses, net of cash acquired					15.2
Intangible assets					3.5
Weighted average useful life					10 years
Goodwill					9.0
Reuel, Inc.
Business Acquisition [Line Items]
Acquisition of businesses, net of cash acquired						11.5
Intangible assets						5.7
Weighted average useful life						12 years
Goodwill expected to be deductible for tax purposes						0
Goodwill						3.4
Litecontrol Corporation
Business Acquisition [Line Items]
Acquisition of businesses, net of cash acquired						45.3
Intangible assets						16.7
Weighted average useful life						12 years
Goodwill						12.0
Powerohm Resistors, Inc.
Business Acquisition [Line Items]
Acquisition of businesses, net of cash acquired							51.1
Intangible assets							22.3
Weighted average useful life							19 years
Goodwill expected to be deductible for tax purposes							0
Goodwill							32.5
English Road Holdings, LLC
Business Acquisition [Line Items]
Acquisition of businesses, net of cash acquired							32.4
Intangible assets							5.2
Weighted average useful life							22 years
Goodwill							13.8
Fiber and Cable Accessories, Inc.
Business Acquisition [Line Items]
Acquisition of businesses, net of cash acquired							8.3
Intangible assets							4.3
Weighted average useful life							19 years
Goodwill							$ 2.9