INCOME TAXES - Deferred Tax Liability (Asset) (Details) - USD ($) $ in Thousands	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013
Deferred tax liabilities:
Goodwill amortization	$ 71,911				$ 69,014
Acquired Intangibles	15,147				16,494
Software development costs					3,257
Prepaid expenses	1,887				1,674
Sec. 481(a) adjustments	786
Other	117				6
Total deferred tax liabilities	89,848				90,445
Deferred tax assets:
Property, plant and equipment	2,304				133
Net operating loss carryforwards	5,108				6,039
Accrued expenses	41,431				25,883
Deferred benefit plan compensation	9,119				8,351
Provision for doubtful accounts	40,403				25,507
Inventory	36,347				28,039
Restricted stock	3,672				3,608
Capital leases	641				318
Deferred rent	2,060				1,660
Refund liabilities	1,143				935
Interest on Seller Notes	906				578
Other	1,734				940
Total deferred tax assets	144,868				101,991
Valuation allowance	(5,692)				(1,259)
Net deferred tax assets	139,176				100,732
Net deferred tax asset	49,328				10,287
Current:
Deferred tax assets	114,560				76,242
Deferred tax liabilities	(926)				(6)
Valuation allowance	(4,382)				(620)
Net current deferred income tax asset	109,252	$ 70,333	$ 70,789	$ 71,569	75,616	$ 64,209	$ 64,153	$ 61,055
Non-current:
Deferred tax assets	30,308				25,749
Deferred tax liabilities	(88,922)				(90,439)
Valuation allowance	(1,310)				(639)
Net non-current deferred income tax liability	(59,924)	$ (62,786)	$ (62,338)	$ (61,640)	(65,329)	$ (65,906)	$ (65,935)	$ (66,489)
Net deferred tax asset	$ 49,328				$ 10,287