Segment Information - Summary of Financial Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenue:
Total Revenue	$ 98,248	$ 79,133	$ 264,803	$ 235,876
Depreciation and amortization:
Total Depreciation and amortization	4,386	3,226	9,561	9,955
Income (loss) from operations before interest and income taxes:
Total income from operations before interest and income taxes	1,262	3,308	13,874	15,042
Interest (expense) income:
Total Interest (expense) income	(1,305)	121	(1,167)	1,002
Income tax expense (benefit):
Total Income tax expense	224	785	3,509	4,291
Capital expenditures:
Total Capital expenditures	2,785	1,278	5,813	4,171
Corporate and Other
Revenue:
Total Revenue	(30)	(67)	(156)	(182)
Depreciation and amortization:
Total Depreciation and amortization	10	10	31	31
Income (loss) from operations before interest and income taxes:
Total income from operations before interest and income taxes	(6,012)	(4,550)	(17,444)	(14,288)
Interest (expense) income:
Total Interest (expense) income	(1,348)	41	(1,344)	735
Income tax expense (benefit):
Total Income tax expense	(2,261)	(1,114)	(6,287)	(3,537)
APUS Segment | Operating Segments
Revenue:
Total Revenue	65,906	69,659	210,321	210,376
Depreciation and amortization:
Total Depreciation and amortization	2,246	3,057	7,071	9,451
Income (loss) from operations before interest and income taxes:
Total income from operations before interest and income taxes	7,825	7,392	30,969	29,785
Interest (expense) income:
Total Interest (expense) income	41	78	171	251
Income tax expense (benefit):
Total Income tax expense	2,606	1,769	9,673	7,944
Capital expenditures:
Total Capital expenditures	1,159	1,271	2,973	4,015
RU Segment | Operating Segments
Revenue:
Total Revenue	21,132	0	21,132	0
Depreciation and amortization:
Total Depreciation and amortization	1,935	0	1,935	0
Income (loss) from operations before interest and income taxes:
Total income from operations before interest and income taxes	(999)	0	(999)	0
Interest (expense) income:
Total Interest (expense) income	0	0	0	0
Income tax expense (benefit):
Total Income tax expense	(371)	0	(371)	0
Capital expenditures:
Total Capital expenditures	1,259	0	1,259	0
HCN Segment | Operating Segments
Revenue:
Total Revenue	11,240	9,541	33,506	25,682
Depreciation and amortization:
Total Depreciation and amortization	195	159	524	473
Income (loss) from operations before interest and income taxes:
Total income from operations before interest and income taxes	448	466	1,348	(455)
Interest (expense) income:
Total Interest (expense) income	2	2	6	16
Income tax expense (benefit):
Total Income tax expense	250	130	494	(116)
Capital expenditures:
Total Capital expenditures	$ 367	$ 7	$ 1,581	$ 156