Valuation And Qualifying Accounts (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Doubtful Accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at the beginning of the period		$ 3,825	$ 4,412	$ 3,989
Additions	[1]	224	884	2,969
Deduction		(868)	(1,471)	(2,546)
Balance at the end of the period		3,181	3,825	4,412
Valuation Allowance of Deferred Tax Assets
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at the beginning of the period		1,984	2,311	77
Additions	[1]	20	75	2,234
Deduction		(1,172)	(402)	0
Balance at the end of the period		$ 832	$ 1,984	$ 2,311

[1] Reductions in/charges to revenues and expenses.