Debt (Detail) (USD $)	3 Months Ended			3 Months Ended			3 Months Ended				12 Months Ended
	Mar. 31, 2014 installment	Dec. 31, 2013	Mar. 31, 2014 Interest rate swap	Mar. 31, 2014 Federal Funds rate	Mar. 31, 2014 Euro Dollar rate	Mar. 31, 2014 Euro Dollar rate Federal Funds rate	Mar. 31, 2014 Term loans		Mar. 31, 2014 Revolver loans	Mar. 31, 2014 Revolver loans Letter of credit	Dec. 31, 2012 Connecticut Economic Development Program	Dec. 31, 2013 Connecticut Economic Development Program
Debt Instrument [Line Items]
Debt instruments, maturity duration							5 years
Line of credit facility, maximum borrowing capacity							$ 150,000,000.0		$ 600,000,000.0	$ 40,000,000.0	$ 5,000,000.0
Line of credit facility, additional borrowing capacity	250,000,000.0
Line of credit facility, frequency of payments							16 consecutive quarterly installments
Line of credit facility, frequency of payments in quarterly installments	16
Debt instrument, maturity date							Mar. 07, 2018		Mar. 07, 2018
Debt instrument, interest, additional interest above federal fund rate				0.50%
Debt instrument, period principal payments are deferred											5 years
Debt Instrument, interest, additional interest above eurodollar rate	1.00%
Minimum applicable margin rate					1.25%	0.25%
Maximum applicable margin rate					1.75%	0.75%
Debt Instrument, interest rate increase	2.00%
Contractual annualized interest rate							1.61%	[1]
Debt instrument, interest base rate							0.23%
Debt instrument, interest, additional interest above base rate							1.38%
Derivative, fixed interest rate	2.26%
Notional amount of interest rate derivatives	210,270,000	261,325,000	200,000,000.0
Debt instrument, interest rate at period end	3.26%
Line of credit facility, remaining borrowing capacity	389,200,000
Line of credit facility, interest rate description											10 year maturity and bears a 3.0% fixed rate of interest
Debt instrument, maturity period											10 years
Debt instrument, fixed interest rate												3.00%
Line of credit facility, decrease, forgiveness											2,500,000.0
Debt instrument, forgiveness period under the terms of the loan											5 years
Interest rate, fair value hedge derivative at fair value, net (negative fair value)			5,700,000
Letters of credit outstanding, amount	$ 9,600,000

[1] The contractual annual interest rate as of March 31, 2014 on both the term loan and the revolver was 1.61%, which consisted of a floating Eurodollar base rate of 0.23% plus a margin of 1.38%. However, the Company has an interest rate swap contract which converts the floating Eurodollar base rate to a 2.26% fixed base rate on the first $200.0 million of Company borrowings (see below). As a result, the Company’s annual effective interest rate on its total outstanding debt as of March 31, 2014, was 3.26%.