Business Combinations and Discontinued Operations - Additional information (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2021 USD ($) Number	Jun. 30, 2020 USD ($)
Increase in income tax receivable	$ 28,165	$ 70,487
Pediatric Orthopedic Practice And Multi Location Pediatric Urgent Care Practice [Member]
Number of other pediatric orthopedic practice acquired | Number	1
Number of other multi location pediatric urgent care practice acquired | Number	1
Business acquisition total consideration	$ 12,200
Business acquisition consideration paid in cash	7,200
Business combination consideration identifiable as current and long term liabilities	5,000
Goodwill	9,600
Other intangible assets	1,000
Fixed assets	1,600
North American Partners In Anesthesia [Member]
Increase decrease in valuation allowance deferred tax assets	37,000
Increase in income tax receivable	24,000
Tax adjustments, sttlements and unusual provisions	9,000
Increase in deferred tax assets	17,000
Anesthesiology Services Medical Group [Member]
Incremental loss on sale, net	19,100
Radiology Services Medical Group [Member]
Incremental loss on sale, net	$ 2,300