Acquisition Activity - Assets Acquired and Liabilities (Details) - USD ($)				12 Months Ended
	Jan. 01, 2022	Sep. 01, 2021	Aug. 10, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Assets acquired:
Intangible assets	$ 965,000	$ 86,500,000
Liabilities assumed:
Goodwill				$ 112,593,000	$ 243,486,000	$ 26,563,000
Rasmussen
Business Acquisition [Line Items]
Cash and cash equivalents		329,000,000
Working capital adjustment and additional cash contributions		2,333,000
Total consideration		331,333,000
Assets acquired:
Cash and cash equivalents		5,200,000
Accounts receivable		10,700,000
Prepaid expenses		4,600,000
Property and equipment, net		36,996,000
Operating lease assets		75,800,000
Deferred tax asset		3,049,000
Intangible assets		86,500,000
Other assets		600,000
Total assets acquired		223,445,000
Liabilities assumed:
Accounts payable and accrued liabilities		7,342,000
Deferred revenue		22,700,000
Operating lease liabilities, current		11,200,000
Operating lease liabilities, long-term		67,000,000
Other liabilities		1,300,000
Total liabilities assumed		109,542,000
Net assets acquired		113,903,000
Goodwill		$ 217,430,000		86,000,000	$ 217,400,000
Graduate School USA
Business Acquisition [Line Items]
Cash and cash equivalents	1,000,000		$ 1,000,000
Working capital adjustment and additional cash contributions	(2,450,000)
Total consideration	(1,450,000)
Assets acquired:
Accounts receivable	4,282,000
Prepaid expenses	1,096,000
Property and equipment, net	400,000
Operating lease assets	31,635,000
Intangible assets	965,000
Total assets acquired	38,378,000
Liabilities assumed:
Accounts payable and accrued liabilities	810,000
Deferred revenue	1,969,000
Operating lease liabilities, current	1,179,000
Operating lease liabilities, long-term	30,779,000
Deferred income taxes	1,263,000
Total liabilities assumed	36,000,000
Net assets acquired	2,378,000
Goodwill			$ 0
Gain on acquisition	$ 3,828,000			$ 3,800,000