Valuation and Qualifying Accounts and Reserves (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for uncollectible accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 109,710	$ 88,814
Charged to Expense	25,605	21,448
Deductions	127,913	552
Balance at End of Year	7,402	109,710	$ 88,814
Allowance for uncollectible accounts [Member] | Previously reported [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year		90,754	86,369
Charged to Expense			17,829
Deductions			13,444
Balance at End of Year			90,754
Valuation allowance for deferred tax assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	28,413	29,846
Charged to Expense	4,068	0
Deductions	0	1,433
Balance at End of Year	$ 32,481	28,413	29,846
Valuation allowance for deferred and prepaid tax assets [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year		$ 29,846	48,662
Charged to Expense			3,991
Deductions			22,807
Balance at End of Year			$ 29,846