Valuation and Qualifying Accounts (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Valuation and Qualifying Accounts Disclosure [Line Items]
Provision For Doubtful Accounts	$ 16,369,000	$ 16,461,000	$ 21,728,000
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Balance, Beginning Balance	14,200,000	21,000,000	17,400,000
Provision For Doubtful Accounts	16,400,000	16,400,000	21,700,000
Write-Offs	(16,300,000)	(23,200,000)	(18,100,000)
Valuation Allowances and Reserves, Balance, Ending Balance	14,300,000	14,200,000	21,000,000
Allowance for Doubtful Accounts - Discontinued Operations [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Provision For Doubtful Accounts	100,000	600,000	700,000
Estimated Revenue Adjustments [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Valuation Allowances and Reserves, Balance, Beginning Balance	3,900,000	6,400,000	6,800,000
Provision for Estimated Revenue Adjustments	5,100,000	9,400,000	10,600,000
Write-Offs	(5,900,000)	(11,900,000)	(11,000,000)
Valuation Allowances and Reserves, Balance, Ending Balance	3,100,000	3,900,000	6,400,000
Estimated Revenue Adjustments, Discontinued Operations [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Provision for Estimated Revenue Adjustments	$ 100,000	$ 400,000	$ 700,000