EMPLOYEE BENEFITS (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jan. 31, 2004 payment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
EMPLOYEE BENEFITS
Matching employer contributions under 401(k) Savings and Retirement plan		$ 5,900	$ 6,700	$ 6,600
Supplemental Executive Retirement Plan (SERP)
Number of annual payments upon retirement | payment	15
Average remaining service period		11 years 6 months	12 years 6 months
Change in Benefit Obligation
Benefit obligation at the beginning of the year		$ 21,304	$ 21,885	23,054
Service cost		340	390	386
Interest cost		711	740	703
Payments		(1,913)	(1,847)	(1,853)
Actuarial (gain) loss		351	136	(405)
Benefit obligation at the end of the year		20,793	21,304	21,885
Unfunded status					$ 20,793
Net amount recognized					20,793
Amounts Recognized in the Consolidated Balance Sheet
Current accrued expenses and other current liabilities					1,913	$ 1,913
Non-current other liabilities					18,880	19,391
Total accrued liabilities					20,793	21,304
Other comprehensive (loss) income - gross actuarial gains (losses)					(400)	$ (100)	$ 400
Cash Surrender Value from DB SERP					$ 17,100
Weighted average assumptions used to determine the benefit obligation and net benefit cost
Discount rate, to determine the benefit obligation (as a percent)					3.27%	3.54%	3.64%
Average rate of increase in compensation, to determine the benefit obligation (as a percent)					3.00%	3.00%	3.00%
Future payments under the Plan
2018					$ 1,913
2019					1,913
2020					1,913
2021					1,913
2022					1,913
Thereafter					11,228
Total		$ 21,304	$ 21,885	$ 23,054	20,793	$ 21,304	$ 21,885
Estimated accumulated obligation benefit					3,000	2,000
Funded estimated accumulated obligation benefit					2,300	1,400
Unfunded estimated accumulated obligation benefit					$ 700	$ 600