STOCK PLANS AND STOCK BASED COMPENSATION - DEFERRED COMPENSATION (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Director
Shares Deferred
Outstanding, beginning of period (in shares)	76,326	67,363
Deferred base salaries and dividend equivalents converted to stock units	14,371	13,930
Stock units converted to Class A Common Shares	(3,897)	(4,967)
Outstanding, end of period (in shares)	86,800	76,326	67,363
Vested (in shares)	86,800
Weighted Average Market Price at Date of Deferral
Outstanding, beginning of period (in dollars per share)	$ 27.38	$ 27.65
Deferred base salaries and dividend equivalents converted to stock units (in dollars per share)	46.28	32.20
Stock units converted to Class A Common Shares (in dollars per share)	39.09	44.58
Outstanding, end of period (in dollars per share)	29.98	$ 27.38	$ 27.65
Vested (in dollars per share)	$ 29.98
Deferred compensation expense	$ 417	$ 352	$ 213
Director | Minimum
Deferred Compensation
Specified period during which board and committee fees may be deferred by participants	2 years
Director | Maximum
Deferred Compensation
Specified period during which board and committee fees may be deferred by participants	5 years
Key Employees
Deferred Compensation
Vesting period after Company match	5 years
Shares Deferred
Outstanding, beginning of period (in shares)	48,886	23,378
Deferred base salaries and dividend equivalents converted to stock units	9,186	12,754
Matching stock units credited (in shares)	9,138	12,754
Matching stock units forfeited (in shares)	(1,892)
Outstanding, end of period (in shares)	65,318	48,886	23,378
Vested (in shares)	48,120
Unvested (in shares)	17,198
Weighted Average Market Price at Date of Deferral
Outstanding, beginning of period (in dollars per share)	$ 37.37	$ 41.75
Deferred base salaries and dividend equivalents converted to stock units (in dollars per share)	47.69	32.17
Matching stock units credited (in dollars per share)	47.69	32.17
Matching stock units forfeited (in dollar per share)	47.92
Outstanding, end of period (in dollars per share)	39.96	$ 37.37	$ 41.75
Vested (in dollars per share)	39.96
Unvested (in dollars per share)	$ 39.96
Deferred compensation expense	$ 429	$ 408	$ 319