Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Lower Limit
Significant Accounting Policies [Line Items]
Marketability discount		10.00%
Duration of the sale restrictions		3 months
Upper Limit
Significant Accounting Policies [Line Items]
Marketability discount		20.00%
Duration of the sale restrictions		6 months
Percentage of voting interest held by the company for investments accounted for under the equity method		5.00%	5.00%
Investments in limited partnerships | Lower Limit
Significant Accounting Policies [Line Items]
Percentage of voting interest held by the company for investments accounted for under the equity method		5.00%
Investments in limited partnerships | Upper Limit
Significant Accounting Policies [Line Items]
Percentage of ownership interest held by the company for investments accounted for under the cost method		5.00%
Privately Held Companies | Lower Limit
Significant Accounting Policies [Line Items]
Percentage of voting interest held by the company for investments accounted for under the equity method		20.00%
Accounting Standards Update 2014-01
Significant Accounting Policies [Line Items]
Cumulative effect of adopting ASU 2014-01	[1]			$ (3,299)
Accounting Standards Update 2014-01 | Retained earnings
Significant Accounting Policies [Line Items]
Cumulative effect of adopting ASU 2014-01	[1]	$ 4,700		$ (3,299)
Accounting Standards Update 2015-03
Significant Accounting Policies [Line Items]
Debt issuance costs		$ 4,800	$ 2,100
China Joint Venture investment | Other investments | Equity method accounting
Significant Accounting Policies [Line Items]
Ownership percentage of each Fund		50.00%	50.00%

[1] See Note 2— "Summary of Significant Accounting Policies-Adoptions of New Accounting Standards” of the “Notes to the Consolidated Financial Statements” under Part II, Item 8 of this report for additional details.