Income Taxes - Significant Components of Deferred Income Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Components Of Deferred Income Tax Assets And Liabilities [Line Items]
Allowance for uncollectible accounts	$ 42,425	$ 44,232
Reserves and accruals	52,519	43,345
Stock-based compensation	16,457	18,444
Net operating loss carryforward	6,385	5,624
Property and equipment	1,310	802
Other	446	509
Total deferred tax assets	119,542	112,956
Amortization	(162,399)	(136,670)
Accrual to cash adjustment	(37,818)	(33,129)
Total deferred tax liabilities	(200,217)	(169,799)
Net deferred tax (liability) asset	(80,675)	(56,843)
Current [Member]
Components Of Deferred Income Tax Assets And Liabilities [Line Items]
Allowance for uncollectible accounts	42,425	44,232
Reserves and accruals	49,128	39,942
Stock-based compensation	10,914	11,856
Net operating loss carryforward	6,385	5,624
Other	446	509
Total deferred tax assets	109,298	102,163
Accrual to cash adjustment	(37,818)	(33,129)
Total deferred tax liabilities	(37,818)	(33,129)
Net deferred tax (liability) asset	71,480	69,034
Non-Current [Member]
Components Of Deferred Income Tax Assets And Liabilities [Line Items]
Reserves and accruals	3,391	3,403
Stock-based compensation	5,543	6,588
Property and equipment	1,310	802
Total deferred tax assets	10,244	10,793
Amortization	(162,399)	(136,670)
Total deferred tax liabilities	(162,399)	(136,670)
Net deferred tax (liability) asset	$ (152,155)	$ (125,877)