Schedule II Valuation and Qualifying Accounts (Details) - Allowance for receivables - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 8,077	$ 13,012	$ 10,699
Additions/ (Reductions)	4,671	6,759	12,714
Write-offs	(6,472)	(11,694)	(10,401)
Balance at end of period	6,276	8,077	13,012
American Public Education Segment
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	4,712	10,286	8,461
Additions/ (Reductions)	2,631	4,861	11,203
Write-offs	(4,090)	(10,435)	(9,378)
Balance at end of period	3,253	4,712	10,286
Hondros College of Nursing Segment
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	3,365	2,726	2,238
Additions/ (Reductions)	2,040	1,898	1,511
Write-offs	(2,382)	(1,259)	(1,023)
Balance at end of period	$ 3,023	$ 3,365	$ 2,726