Debt (Detail)		12 Months Ended
	Jan. 20, 2017 USD ($)	Dec. 31, 2016 USD ($) installment contract outstanding_contract	Dec. 31, 2012 USD ($)	Dec. 31, 2015 USD ($) outstanding_contract
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 1,800,000,000.0
Debt instrument, interest, additional interest above eurodollar rate		1.00%
Contract notional amount		$ 786,946,000		$ 893,610,000
Current portion of long-term debt		30,000,000		$ 35,000,000
Long-term debt, net of deferred financing fees		$ 672,500,000
Debt instrument, interest rate at period end		2.80%
Number of Outstanding Contracts | outstanding_contract		87		105
Federal Funds rate
Debt Instrument [Line Items]
Debt instrument, interest, additional interest above federal fund rate		0.50%
Euro Dollar rate | Federal Funds rate
Debt Instrument [Line Items]
Minimum applicable margin rate		0.125%
Maximum applicable margin rate		0.50%
Interest Rate Contract
Debt Instrument [Line Items]
Contract notional amount		$ 700,000,000
Interest rate swap
Debt Instrument [Line Items]
Contract notional amount		$ 700,000,000.0
Number of Outstanding Contracts | contract		3
Derivative, term of contract		30 days
Interest rate derivative hedge, negative fair value		$ 2,300,000		$ 5,100,000
Euro Dollar rate
Debt Instrument [Line Items]
Minimum applicable margin rate		1.125%
Maximum applicable margin rate		3.00%
Minimum | Interest rate swap
Debt Instrument [Line Items]
Derivative, fixed interest rate		1.53%
Maximum | Interest rate swap
Debt Instrument [Line Items]
Derivative, fixed interest rate		1.60%
Term loan
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 600,000,000
Debt instrument term		5 years
Interest rate at period end		2.15%
Debt instrument, interest base rate		0.77%
Debt instrument, interest, additional interest above base rate		1.38%
Connecticut Economic Development Program
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity			$ 5,000,000
Debt instrument, fixed interest rate			3.00%
Line of credit facility, decrease, forgiveness			$ 2,500,000
Debt instrument, debt forgiveness		$ 2,500,000.0
Letter of credit
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		50,000,000
Letters of credit outstanding		8,500,000
Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, current borrowing capacity		$ 1,200,000,000
Line of credit facility, frequency of payments in quarterly installments | installment		16
Interest rate at period end		2.15%
Line of credit facility, remaining borrowing capacity		$ 1,100,000,000
Subsequent Event
Debt Instrument [Line Items]
Line of credit, capacity available for specific purpose	$ 2,275,000,000.000
Subsequent Event | Secured Debt
Debt Instrument [Line Items]
Debt instrument term	7 years
Line of credit, capacity available for specific purpose	$ 1,375,000,000.000
Subsequent Event | Unsecured Debt
Debt Instrument [Line Items]
Line of credit, capacity available for specific purpose	$ 600,000,000.0
Bridge Loan | Subsequent Event
Debt Instrument [Line Items]
Debt instrument term	11 months 29 days
Line of credit, capacity available for specific purpose	$ 300,000,000.0