Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 7,921	$ 8,613	$ 8,250
Charged to cost and expenses	2,261	219	672
Write-offs (recoveries) of doubtful accounts	1,496	911	309
Balance at end of period	8,686	7,921	8,613
Student Loan [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	21,317	19,361	21,026
Charged to cost and expenses	16,529	19,834	17,858
Write-offs (recoveries) of doubtful accounts	18,398	17,878	19,523
Balance at end of period	$ 19,448	$ 21,317	$ 19,361