STOCK-BASED COMPENSATION - Three Year Vest Restricted Shares (Details) - Three-Year Vesting - USD ($) $ / shares in Units, $ in Millions									12 Months Ended
	Jan. 23, 2019	Jan. 24, 2018	Aug. 04, 2017	Jan. 25, 2017	Jan. 27, 2016	Feb. 09, 2015	Jan. 28, 2015	Jan. 22, 2014	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restricted Shares
Stock-based compensation
Vesting per year (as a percent)	33.00%	33.00%		33.00%	33.00%			33.00%
Shares
Outstanding (in shares)									34,952	37,390	37,504
Granted (in shares)	20,696	17,712		17,451	21,100			14,500	20,696	17,712	17,451
Vested (in shares)									(18,053)	(18,883)	(17,298)
Forfeited (in shares)										(1,267)	(267)
Outstanding (in shares)									37,595	34,952	37,390
Weighted Average Fair Value
Outstanding (in dollars per share)									$ 58.07	$ 51.39	$ 47.53
Granted (in dollars per share)									58.78	65.33	55.06
Vested (in dollars per share)									54.43	51.57	46.70
Forfeited (in dollars per share)										59.39	52.51
Outstanding (in dollars per share)									$ 60.21	$ 58.07	$ 51.39
Compensation cost
Unrecognized compensation cost									$ 1.2
Weighted average period of recognition of unrecognized compensation cost									1 year 8 months 12 days
Restricted Shares | Certain employees, excluding Mr. Albright
Stock-based compensation
Vesting per year (as a percent)							33.00%
Shares
Granted (in shares)						8,000	11,700
Restricted Shares | Mr. Albright
Stock-based compensation
Vesting per year (as a percent)						33.00%
Equity Award Agreements
Award agreements
Period after change of control for equity award to fully vest upon termination of employment without cause or resignation			24 months