Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Reconciliation [Line Items]
Estimated effective income tax rate	29.00%	37.00%	42.00%
Effective tax rate impacted by net tax benefit	$ 15,505,000
Recognized tax benefit from uncertain tax positions	31,000,000
Reduction on deferred tax assets	15,500,000
Valuation allowance	(2,397,000)	(35,000)	(1,600,000)
Deferred tax assets related to net operating losses for federal income tax purposes	21,547,000	23,705,000
Ownership percentage	50.00%
Percentage increasing ownership	5.00%
Pre-tax net operating loss carryovers	66,500,000
Built-in losses annual limitation	4,200,000
Reduced unrecognized tax benefits	32,602,000	1,346,000	191,000
Net of federal benefit	31,000,000
Interest or penalties related to uncertain tax positions	0	0	0
Recognized tax benefits	39,349,000	44,778,000	27,030,000
Connecticut [Member]
Income Tax Reconciliation [Line Items]
Open tax year	2001
New York [Member]
Income Tax Reconciliation [Line Items]
Open tax year	2000
Tax Year 2011 [Member]
Income Tax Reconciliation [Line Items]
Decrease in net operating loss carry-forwards	15,500,000
Domestic Tax Authority [Member]
Income Tax Reconciliation [Line Items]
Deferred tax assets related to net operating losses for federal income tax purposes	41,000,000
Domestic Tax Authority [Member] | Minimum [Member]
Income Tax Reconciliation [Line Items]
Operating loss carry-forwards, expiration beginning year	2029
State and Local Jurisdiction [Member]
Income Tax Reconciliation [Line Items]
Deferred tax assets related to net operating losses for federal income tax purposes	7,200,000
State and Local Jurisdiction [Member] | Minimum [Member]
Income Tax Reconciliation [Line Items]
Operating loss carry-forwards, expiration beginning year	2016
Stock-based Incentive Plans [Member]
Income Tax Reconciliation [Line Items]
Recognized tax benefits	$ 24,800,000