Business Combinations, Assets Held for Sale and Discontinued Operations - Additional information (Detail) $ in Thousands		3 Months Ended		9 Months Ended
	May 06, 2020 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Mar. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Net incremental loss on the sale of MedData		$ (38,392)	$ (1,268,803)	$ (718,125)	$ (1,539,314)
Goodwill		1,480,668		1,480,668			$ 1,479,850
Pediatric Subspecialty Practice [Member]
Business acquisition total consideration				2,100
Business acquisition consideration paid in cash				1,900
Goodwill		800		800
Other intangible assets		1,300		$ 1,300
Number of other pediatric subspecialty practices acquired				1
Business acquisition contingent consideration liability		200		$ 200
Deferred Tax Assets, Goodwill and Intangible Assets		4,000		4,000
North American Partners In Anesthesia [Member]
Preliminary and incremental gain loss on sale				648,700
Increase decrease in valuation allowance deferred tax assets				419,000
Net incremental loss on the sale of MedData		(4,698)	$ (1,176,187)	(684,063)	$ (1,139,525)
Proceeds from Divestiture of Businesses	$ 50,000
Maximum consideration receivable	250,000
Accounts receivable retained						$ 110,000
North American Partners In Anesthesia [Member] | Tax Year Two Thousand and Twenty Five [Member]
Capital loss carry forward		1,680,000		1,680,000
North American Partners In Anesthesia [Member] | Maximum [Member]
Maximum consideration receivable	250,000
North American Partners In Anesthesia [Member] | Minimum [Member]
Maximum consideration receivable	$ 0
Divestiture of MedData [Member]
Net incremental loss on the sale of MedData				5,800
Radiology Services Medical Group [Member]
Maximum consideration receivable		$ 885,000		885,000
Non-cash charge against goodwill				43,000
Deferred Tax Assets Goodwill [Member] | Pediatric Subspecialty Practice [Member]
Non-cash charge against goodwill				$ 47,000