NATURE OF OPERATIONS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Accounting (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other long-term assets	$ 10,746	$ 14,318
Long-term deferred income tax liability	47,036	30,025
Long-term obligations	371,365	296,819
Accounting Standards Update 2015-17 | Adjustments for New Accounting Principle, Early Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Current deferred tax asset	4,600
Long-term deferred income tax liability	4,600
Accounting Standards Update 2015-03 | Adjustments for New Accounting Principle, Early Adoption
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Other long-term assets	5,300	5,700
Long-term obligations	$ 5,300	$ 5,700