Summary of Significant Accounting Policies - Components of Property, Building and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property, building and equipment, gross	$ 252,353	$ 221,087
Less accumulated depreciation	98,394	82,721
Property, building and equipment, net	153,959	138,366
Land
Property, Plant and Equipment [Line Items]
Property, building and equipment, gross	7,339	7,339
Building and leasehold improvements
Property, Plant and Equipment [Line Items]
Property, building and equipment, gross	105,431	40,766
Transportation equipment
Property, Plant and Equipment [Line Items]
Property, building and equipment, gross	19,898	19,821
Fixed equipment
Property, Plant and Equipment [Line Items]
Property, building and equipment, gross	365	365
Office furniture and medical equipment
Property, Plant and Equipment [Line Items]
Property, building and equipment, gross	116,732	104,557
Construction in progress
Property, Plant and Equipment [Line Items]
Property, building and equipment, gross	$ 2,588	$ 48,239