RSA GRANTS (Details 6) - $ / shares		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restricted stock awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value		$ 70.55
Restricted stock awards [Member] | Employee Stock Plan [Member] | 2/27/2020 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		46,550
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]	$ 70.24
Vesting terms		Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 4/15/2020 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		880
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]	$ 70.02
Vesting terms		Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 2/21/2019 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			43,250
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]		$ 83.87
Vesting terms			Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 3/15/2019 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			600
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]		$ 79.55
Vesting terms			Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 4/1/2019 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			1,090
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]		$ 82.62
Vesting terms			Ratably over 3 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 2/15/2018 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				39,950
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 71.75
Vesting terms				Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 2/27/2018 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				1,150
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 72.60
Vesting terms				Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 5/15/2018 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				530
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 74.00
Vesting terms				Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 11/15/2018 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				560
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 77.78
Vesting terms				Ratably over 5 years from grant date
Restricted stock awards [Member] | Non Employee Director Stock Plan Member | 5/22/2018 | Immediately upon grant date
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				6,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 76.58
Vesting terms				Immediately upon grant date
Restricted stock awards [Member] | Two Thousand Eighteen Nonemployee Director Stock Plan [Member] | 5/27/2020 | Immediately upon grant date
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		9,438
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]	$ 72.86
Vesting terms		Immediately upon grant date
Restricted stock awards [Member] | Two Thousand Eighteen Nonemployee Director Stock Plan [Member] | 5/21/2019 | Immediately upon grant date
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			6,500
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]		$ 77.08
Vesting terms			Immediately upon grant date
Performance Shares [Member] | Employee Stock Plan [Member] | 2/27/2020 | At The End of Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		17,100
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]	$ 70.24
Vesting terms		The earlier of: the date on which it is determined if the performance goal has been achieved; or, March 31, 2023.
Performance Shares [Member] | Employee Stock Plan [Member] | 2/21/2019 | At The End of Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			15,900
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]		$ 83.87
Vesting terms			The earlier of: the date on which it is determined if the performance goal has been achieved; or, March 31, 2022.
Performance Shares [Member] | Employee Stock Plan [Member] | 2/15/2018 | At The End of Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				16,300
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 71.75
Vesting terms				The earlier of: the date on which it is determined if the performance goal has been achieved; or, March 31, 2021.

[1] The fair value of the restricted stock awards are based upon the average of the high and low prices at which the Company’s common stock traded on the date of grant. The holders of time-vested restricted stock awards participate fully in the rewards of stock ownership of the Company, including voting and dividend rights. The holders of performance-based restricted stock awards do not participate in the rewards of stock ownership of the Company until vested. The holders of all restricted stock awards are not required to pay any consideration to the Company for the awards.