COMMITMENTS AND CONTINGENCIES - (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
COMMITMENTS AND CONTINGENCIES
Maximum employer contribution per eligible employee, amount	$ 18,000
Maximum employer contribution per eligible employee (as a percent)	6.00%
Company match of the first 6%	50.00%
Maximum employee contribution eligible for company match	$ 7,950
Contribution under profit-sharing plan	1,300,000	$ 1,500,000	$ 1,600,000
Aggregate future minimum payments under noncancelable leases
2017	2,894,000
2018	2,299,000
2019	1,762,000
2020	1,793,000
2021	1,040,000
Thereafter	1,001,000
Total minimum lease payments	10,789,000
Rental expense for operating leases	$ 2,900,000	$ 2,900,000	$ 3,600,000