Debt Credit Facility (Details Textual) $ in Millions	9 Months Ended
	Sep. 30, 2017 USD ($)
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, interest rate description	Interest accrues on borrowings under the credit facility at either LIBOR plus a margin between 1.25% and 1.875% per annum or at the base rate plus a margin between 0.25% and 0.875% per annum. Interest is payable quarterly.
Credit facility, current borrowing capacity	$ 350.0
Credit facility additional borrowing capacity available	250.0
Credit facility, maximum borrowing capacity	$ 600.0
Credit facility, maturity date	Jan. 28, 2022
Credit facility, covenant description	The credit facility contains customary negative covenants that, among other things, restrict Cadence’s ability to incur additional indebtedness, grant liens and make certain investments (including acquisitions), dispose of certain assets and make certain restricted payments, including share repurchases and dividends. In addition, the credit facility contains financial covenants that require Cadence to maintain a debt to EBITDA ratio not greater than 3.00 to 1, with a step up to 3.50 to 1 for one year following an acquisition by Cadence of at least $250.0 million that results in a pro forma leverage ratio between 2.75 to 1 and 3.25 to 1.
Credit facility, covenant compliance	Cadence was in compliance with all financial covenants as of September 30, 2017 and December 31, 2016.
Maximum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, commitment fee percentage	0.30%
Minimum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, commitment fee percentage	0.15%
London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, interest rate spread	1.875%
London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, interest rate spread	1.25%
Base Rate [Member] | Maximum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, interest rate spread	0.875%
Base Rate [Member] | Minimum [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, interest rate spread	0.25%
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Credit facility, covenant, debt to EBITDA ratio	3
Credit facility, covenant, debt to EBITDA ratio after step up triggered by acquisition	3.50
Credit facility, covenant, required business acquisition consideration, minimum	$ 250.0
Revolving Credit Facility [Member] | Maximum [Member]
Line of Credit Facility [Line Items]
Credit facility, covenant, pro forma leverage ratio	3.25
Revolving Credit Facility [Member] | Minimum [Member]
Line of Credit Facility [Line Items]
Credit facility, covenant, pro forma leverage ratio	2.75