Allowance for Doubtful Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Doubtful Accounts Receivable [Roll Forward]
Beginning Balance	$ 7,172	$ 6,001	$ 4,768
Accounts written off	(79,054)	(34,723)	(30,609)
Bad debt expense	99,283	35,894	31,842
Ending Balance	$ 27,401	$ 7,172	$ 6,001