Company's Demand Deposits and Temporary Cash Investments (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Risks And Uncertainties [Abstract]
Deposits in FDIC and SIPC-insured institutions under insurance limits	$ 846	$ 617
Deposits in FDIC and SIPC-insured institutions over insurance limits	12,866	130,330
Deposits in foreign banks	27,557	15,303
Total cash and cash equivalents	41,269	146,250
Less outstanding checks and other reconciling items	(6,117)	(32,904)
Cash and cash equivalents	$ 35,152	$ 113,346	$ 43,012	$ 249,509