Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 10,298	$ 10,017	$ 9,939
Charged to cost and expenses	(245)	692	206
Write-offs (recoveries) of doubtful accounts	870	411	128
Balance at end of period	9,183	10,298	10,017
Student Loan [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	8,622	17,603	14,948
Charged to cost and expenses	19,019	12,595	15,336
Write-offs (recoveries) of doubtful accounts	11,959	21,576	12,681
Balance at end of period	$ 15,682	$ 8,622	$ 17,603