BUSINESS COMBINATIONS - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
	Jul. 31, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Business Acquisition [Line Items]
NMI potential earn-out	$ 30,000
Earn-out on acquisition date	400
Fair value of earn-out reversal				$ 200
Goodwill		$ 189,565		189,565		$ 191,088
Acquisition-related charges		2,390	$ 7,162	10,600	$ 10,287
NMI [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	139,600
Goodwill	86,100
NMI goodwill - Deductible for Tax	$ 55,200
Acquisition-related charges						2,500
Goodwill
Business Acquisition [Line Items]
Goodwill, Purchase Accounting Adjustments						1,900
income taxes
Business Acquisition [Line Items]
Goodwill, Purchase Accounting Adjustments						300
Deferred Tax Asset [Domain]
Business Acquisition [Line Items]
Goodwill, Purchase Accounting Adjustments						1,600
Deferred Bonus
Business Acquisition [Line Items]
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed						$ 5,300
Bonus
Business Acquisition [Line Items]
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed		200		3,100
Acquisition-related intangible assets
Business Acquisition [Line Items]
Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed		$ 1,000		$ 4,000