Cash and Cash Equivalents (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 50,423	$ 51,920	$ 28,747	$ 32,114
Cash Deposited In an Affiliate Financial Institution
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	19,600	7,800
Territories Other Than Puerto Rico
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 30,000	$ 35,500