Acquisitions (Details) - USD ($)			3 Months Ended		9 Months Ended
	Dec. 20, 2019	Jan. 03, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Business Acquisition
Goodwill			$ 909,900,000		$ 909,900,000		$ 909,900,000
Business Acquisition, Pro Forma Net Income (Loss)				$ 23,100,000		$ 21,600,000
Earnings (loss) from continuing operations			$ 5,600,000	$ 25,400,000	$ (26,700,000)	$ 28,600,000
Earnings (loss) from continuing operations, per basic share			$ 0.06	$ 0.28	$ (0.29)	$ 0.31
Business Acquisition, Pro Forma Earnings Per Share, Basic				0.25		0.24
Earnings (loss) from continuing operations, per diluted share			$ 0.06	0.27	$ (0.29)	0.31
Business Acquisition, Pro Forma Earnings Per Share, Diluted				$ 0.25		$ 0.23
Credit Facility due January 2, 2024 [Member]
Business Acquisition
Line of Credit Facility, Maximum Borrowing Capacity			$ 400,000,000.0		$ 400,000,000.0
Credit Facility due January 2, 2024 [Member] | Maximum [Member]
Business Acquisition
Line of Credit Facility, Commitment Fee Percentage					0.375%
Credit Facility due January 2, 2024 [Member] | Maximum [Member] | Applicable margin alternate base rate [Member]
Business Acquisition
Debt Instrument, Basis Spread on Variable Rate			1.50%
Credit Facility due January 2, 2024 [Member] | Minimum [Member]
Business Acquisition
Line of Credit Facility, Commitment Fee Percentage					0.225%
Credit Facility due January 2, 2024 [Member] | Minimum [Member] | Applicable margin alternate base rate [Member]
Business Acquisition
Debt Instrument, Basis Spread on Variable Rate			0.50%
ASIC Design Business
Business Acquisition
Payments to Acquire Businesses, Gross	$ 57,900,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	600,000
Goodwill	18,800,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(100,000)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net	$ 57,900,000
Finite-Lived Intangible Asset, Useful Life	6 years
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 1,600,000
Compex Corporation
Business Acquisition
Payments to Acquire Businesses, Gross		$ 11,100,000
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual						$ 6,200,000
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual						$ 100,000
0 | ASIC Design Business
Business Acquisition
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	33,300,000
In Process Research and Development [Member] | ASIC Design Business
Business Acquisition
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 3,700,000