Revenue Recognition - Schedule of Revenues Disaggregated by Service Line (Detail) - USD ($)	3 Months Ended								12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2019
Disaggregation Of Revenue [Line Items]
Total services	$ 145,510,000	$ 141,506,000	$ 136,028,000	$ 129,600,000	$ 147,024,000	$ 148,092,000	$ 146,970,000	$ 150,139,000	$ 552,644,000	$ 592,225,000	$ 595,740,000
Patient Management Services [Member]
Disaggregation Of Revenue [Line Items]
Total services									368,853,000	386,814,000	368,198,000
Network Solutions Services [Member]
Disaggregation Of Revenue [Line Items]
Total services									$ 183,791,000	$ 205,411,000	$ 227,542,000