Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax [Line Items]
Non-current deferred tax assets	$ 27,275	$ 26,418
Valuation allowance	1,431	1,828
Effective income tax rate reconciliation share-based compensation excess tax benefit amount	10,000
Unrecognized tax benefits	37,099	25,911	$ 20,645
Unrecognized tax benefits reductions resulting from settlements with taxing authorities and lapse of applicable statute of limitations	1,700
Unrecognized tax benefits that would impact effective tax rate	33,400
Unrecognized tax benefits that would result adjustments to other tax accounts	3,700
Income tax penalties and interest expense	4,300	3,700
Income tax examination, penalties and interest expense	900	900
Earnings of certain non US subsidiaries indefinitely reinvested	340,000
Undistributed foreign earnings	69,000
Stamford
Income Tax [Line Items]
Effective income tax rate reconciliation, state and local income taxes, amount	(300)	1,600
State and local jurisdiction
Income Tax [Line Items]
Operating loss carryforwards	2,400
Tax credit carryforwards	$ 1,900
State and local jurisdiction | Minimum
Income Tax [Line Items]
Tax credit carryforwards, expiration period	5 years
State and local jurisdiction | Maximum
Income Tax [Line Items]
Tax credit carryforwards, expiration period	6 years
Non US
Income Tax [Line Items]
Operating loss carryforwards	$ 19,500
Foreign tax credit carryforwards	600
Expire within one to five years | State and local jurisdiction
Income Tax [Line Items]
Operating loss carryforwards	$ 100
Expire within one to five years | State and local jurisdiction | Minimum
Income Tax [Line Items]
Operating loss carryforwards expiration period	1 year
Expire within one to five years | State and local jurisdiction | Maximum
Income Tax [Line Items]
Operating loss carryforwards expiration period	5 years
Expire within six to fifteen years | State and local jurisdiction
Income Tax [Line Items]
Operating loss carryforwards	$ 2,300
Expire within six to fifteen years | State and local jurisdiction | Minimum
Income Tax [Line Items]
Operating loss carryforwards expiration period	6 years
Expire within six to fifteen years | State and local jurisdiction | Maximum
Income Tax [Line Items]
Operating loss carryforwards expiration period	15 years
Expire over next twenty years | State and local jurisdiction
Income Tax [Line Items]
Operating loss carryforwards expiration period	20 years
Expire over next twenty years | Non US
Income Tax [Line Items]
Operating loss carryforwards	$ 900
Carried forward indefinitely | Non US
Income Tax [Line Items]
Operating loss carryforwards	18,600
Other assets
Income Tax [Line Items]
Non-current deferred tax assets	27,300	26,400
Other liabilities
Income Tax [Line Items]
Non-current deferred tax liabilities	$ 22,500	$ 23,400