BUSINESS ACQUISITIONS (Details) - USD ($)				3 Months Ended								12 Months Ended
	Nov. 16, 2016	May 31, 2016	Jun. 30, 2014	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Initial cash consideration to acquire business			$ 600,000									$ 81,182,000	$ 0	$ 0
Contingent consideration range, minimum			0
Contingent consideration range, maximum			800,000
Purchase price consideration on acquisition date			1,000,000
Contingent consideration on acquisition date			$ 400,000
Goodwill				$ 56,457,000				$ 3,632,000				56,457,000	3,632,000
Revenue				100,841,000	$ 94,558,000	$ 94,290,000	$ 94,713,000	78,341,000	$ 69,804,000	$ 55,136,000	$ 50,935,000	384,402,000	254,216,000	167,350,000
Operating income (loss)				13,402,000	$ 14,150,000	$ 12,715,000	$ 11,845,000	$ 8,248,000	$ 7,773,000	$ 6,775,000	$ 5,718,000	$ 52,112,000	28,514,000	$ (969,000)
Weighted Average Amortization Life			10 years									3 years 2 months 10 days
Reduction in contingent consideration													200,000
Iron Horse Holdings, LLC [Member]
Business Acquisition [Line Items]
Initial cash consideration to acquire business	$ 80,700,000
Contingent consideration range, maximum	45,000,000.0
Purchase price consideration on acquisition date	103,800,000
Contingent consideration on acquisition date	23,100,000
Goodwill	52,450,000
Revenue	9,200,000
Operating income (loss)	800,000
Acquisition-related costs	400,000												$ 5,500,000
SimpleTuition [Domain]
Business Acquisition [Line Items]
Initial cash consideration to acquire business		$ 4,500,000
Purchase price consideration on acquisition date		5,000,000
Contingent consideration on acquisition date		500,000
Goodwill		375,000
Acquisition-related costs		$ 100,000
Weighted Average Amortization Life		9 years 2 months
Minimum [Member]
Business Acquisition [Line Items]
Contingent consideration on acquisition date				0								$ 0
Maximum [Member]
Business Acquisition [Line Items]
Contingent consideration on acquisition date				$ 45,000,000								$ 45,000,000
Earnout Payment for One Contingent Earnout [Member] | Iron Horse Holdings, LLC [Member]
Business Acquisition [Line Items]
Contingent consideration range, minimum	0
Contingent consideration range, maximum	$ 22,500,000.0