Accounts Receivable - Allowance for Doubtful Accounts Related to Accounts Receivable (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Allowance for Doubtful Accounts Receivable [Roll Forward]
Allowance for doubtful accounts beginning of period	$ 21,903	$ 23,842
Provision for bad debts	6,836	8,145
Write-offs	(4,706)	(10,018)
Allowance for doubtful accounts end of period	$ 24,033	$ 21,969