Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands			12 Months Ended
	Dec. 31, 2018	Aug. 22, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2013
Loss Contingencies [Line Items]
Rent expense			$ 12,200	$ 13,200	$ 13,200
Incentive awarded to the company by the State of Connecticut, total						$ 11,500
Incentive awarded to the company by the State of Connecticut, non-interest bearing loans						8,000
Incentive awarded to the company by the State of Connecticut, grants						$ 3,500
Non-interest bearing incentive loan term			10 years
Forgiveness awarded to the company by the state of Connecticut	$ 7,000
Incentive awarded to the company by the State of Connecticut, other revenue recognized			$ 1,300	1,300	$ 1,400
Incentive awarded to the company by the State of Connecticut, deferred revenue included in other liabilities	$ 4,700		$ 4,700	$ 4,400
The Hartford
Loss Contingencies [Line Items]
Merger Termination Fee		$ 68,250
Maximum
Loss Contingencies [Line Items]
Non-cancellable operating leases expiration year			2032