EMPLOYEE BENEFIT PLANS AND DEFERRED COMPENSATION ARRANGEMENTS (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended		12 Months Ended
	Oct. 31, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
EMPLOYEE BENEFIT PLANS AND DEFERRED COMPENSATION ARRANGEMENTS
Term of service for 401K participation				3 months
Company's contributions to the 401K plan				$ 1,100,000	$ 1,100,000
Aggregate amount paid to employees		$ 14,185,000	$ 12,496,000	$ 28,007,000	$ 25,191,000
Executive Deferred Compensation Arrangements
EMPLOYEE BENEFIT PLANS AND DEFERRED COMPENSATION ARRANGEMENTS
Employers contribution of incentive bonus (as a percent)				25.00%
Deferred plan liability		2,600,000		$ 2,600,000		$ 2,500,000
2008 Salary Continuation Agreement
EMPLOYEE BENEFIT PLANS AND DEFERRED COMPENSATION ARRANGEMENTS
Deferred plan liability		378,000		378,000		421,000
Annual compensation payment amount				$ 100,000
Contractual term				10 years
Commencement age				65 years
2017 Salary Continuation Agreement 2017
EMPLOYEE BENEFIT PLANS AND DEFERRED COMPENSATION ARRANGEMENTS
Deferred plan liability		328,000		$ 328,000		219,000
Annual compensation payment amount	$ 200,000
Contractual term	10 years
Commencement age	70 years
Change of Control and Non‑Competition Agreements | Executive Officers
EMPLOYEE BENEFIT PLANS AND DEFERRED COMPENSATION ARRANGEMENTS
Deferred plan liability		$ 4,400,000		$ 4,400,000		4,400,000
Deferred compensation expense						$ 0