SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES AND PRACTICES - New Accounting Standards - Other (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash and cash equivalents		$ 18,288	$ 26,552	$ 46,216		$ 49,825
Cash flows from investing activities		(25,027)	(33,996)	(75,840)
Effect of adoption		6,780	994
ASU 2016-18
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash and cash equivalents					$ 5,000
Cash flows from investing activities				$ (5,000)
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of adoption		9,110	$ 994
Retained Earnings | ASU 2018-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Effect of adoption		$ 2,300
Minimum | ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 62,000
Maximum | ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	$ 72,000