Debt (Detail) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended					1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2010	Dec. 31, 2010	Dec. 31, 2012	Dec. 31, 2010 Letter of Credit [Member] Revolving Credit Facility [Member]	Dec. 31, 2010 Euro Dollar Rate [Member] Federal Funds Rate [Member]	Dec. 31, 2010 Euro Dollar Rate [Member]	Dec. 31, 2010 Bank Term Loan [Member]	Dec. 31, 2012 Bank Term Loan [Member]	Dec. 31, 2010 Revolver [Member]	Dec. 31, 2012 Connecticut Economic Development Program [Member]	Dec. 31, 2010 Revolving Credit Facility [Member]
Line of Credit Facility, Maximum Borrowing Capacity				$ 40.0			$ 200.0			$ 5.0	$ 400.0
Line Of Credit Facility Additional Borrowing Capacity	150.0	150.0
Line of Credit Facility, Frequency of Payments							19 consecutive quarterly installments
Debt Instrument, Maturity Date							Dec. 22, 2015		Dec. 22, 2015
Line of Credit Facility, Interest Rate Description	either (i) the greatest of: the administrative agent's prime rate; the average rate on overnight federal funds plus 1/2 of 1%; and the eurodollar rate (adjusted for statutory reserves) plus 1%, in each case plus a margin equal to between 0.50% and 1.25% depending on the Company's leverage ratio as of the end of the four consecutive fiscal quarters most recently ended, or (ii) the eurodollar rate (adjusted for statutory reserves) plus a margin equal to between 1.50% and 2.25%, depending on the Company's leverage ratio as of the end of the four consecutive fiscal quarters most recently ended									10 year maturity and bears a 3% fixed rate of interest
Debt Instrument Interest Additional Interest Above Eurodollar Rate	1.00%
Average Rate on Overnight Federal Funds Plus 1/2 of	1.00%
MinimumApplicableMarginRate					0.50%	1.50%
Maximum Applicable Margin Rate					1.25%	2.25%
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax		3.3
Write off of Deferred Debt Issuance Cost		0.4
Debt Instrument Interest Base Rate								0.31%
Debt Instrument Interest Additional Interest Above Base Rate								1.50%
Derivative, Fixed Interest Rate			2.26%
Notional Amount of Interest Rate Derivatives			200.0
Debt Instrument, Interest Rate at Period End			3.76%
Line of Credit Facility, Remaining Borrowing Capacity			346.6
Line of Credit Facility, Decrease, Forgiveness										2.5
Interest Rate Fair Value Hedge Derivative at Fair Value, Net			10.0
Letters of Credit Outstanding, Amount			$ 10.1