Consolidated Valuation and Qualifying Accounts (Detail) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning Balance	$ 8,221	$ 5,790	$ 4,955
Charges to costs and expenses	31,532	23,447	15,230
Ending Balance	7,488	8,221	5,790
Deductions	$ (32,265)	$ (21,016)	$ (14,395)