RSA GRANTS (Details 6) - $ / shares		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
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		$ 63.07
Restricted stock awards [Member] | Employee Stock Plan [Member] | Date Sixteen [Member] | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		1,200
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]	$ 62.53
Vesting terms		Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | Date Seventeen [Member] | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		34,150
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]	$ 63.10
Vesting terms		Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | Date eighteen [Member] | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		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]	$ 65.63
Vesting terms		Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | Date nineteen [Member] | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		1,500
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]	$ 64.14
Vesting terms	[2]	Once on November 30, 2017 (2)
Restricted stock awards [Member] | Employee Stock Plan [Member] | Date Twenty [Member] | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		1,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]	$ 64.03
Vesting terms		Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | Date Twenty Two [Member] | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		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]	$ 66.18
Vesting terms		Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 2/11/2016 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			51,475
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]		$ 41.96
Vesting terms			Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 3/1/2016 | 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]		$ 44.37
Vesting terms			Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 9/19/2016 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			800
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]		$ 52.92
Vesting terms			Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 11/7/2016 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			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]		$ 54.28
Vesting terms			Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 2/11/2015 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				31,500
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 39.42
Vesting terms				Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 2/12/2015 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				25,910
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 40.03
Vesting terms				Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 3/19/2015 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				3,800
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 43.56
Vesting terms				Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 4/27/2015 | At The End of Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				625
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 41.61
Vesting terms				At the end of 3 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 4/27/2015 | At The End of Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				1,875
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 41.61
Vesting terms				At the end of 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 10/13/2015 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				1,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 46.09
Vesting terms				Ratably over 5 years from grant date
Restricted stock awards [Member] | Employee Stock Plan [Member] | 10/20/2015 | Ratably Over Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				2,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 46.47
Vesting terms				Ratably over 5 years from grant date
Restricted stock awards [Member] | Non Employee Director Stock Plan Member | Date Twenty One [Member] | At The End of Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		7,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]	$ 61.95
Vesting terms	[3]	At the end of 5 years from grant date (3)
Restricted stock awards [Member] | Non Employee Director Stock Plan Member | 5/24/2016 | At The End of Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			8,700
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]		$ 48.34
Vesting terms	[3]		At the end of 5 years from grant date (3)
Restricted stock awards [Member] | Non Employee Director Stock Plan Member | 11/14/2016 | At The End of Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			725
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]		$ 63.43
Vesting terms	[4]		Once on May 24, 2021 (4)
Restricted stock awards [Member] | Non Employee Director Stock Plan Member | 5/27/2015 | At The End of Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				8,800
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 45.02
Vesting terms	[3]			At the end of 5 years from grant date (3)
Restricted stock awards [Member] | Non Employee Director Stock Plan Member | 7/14/2015 | At The End of Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				800
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 47.82
Vesting terms	[5]			Once on May 27, 2020 (5)
Performance Shares [Member] | Employee Stock Plan [Member] | 2/11/2016 | At The End of Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted			20,450
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]		$ 41.96
Vesting terms			The earlier of: the date on which it is determined if the performance goal has been achieved; or, March 31, 2019.
Performance Shares [Member] | Employee Stock Plan [Member] | 2/12/2015 | At The End of Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted				21,780
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]			$ 40.03
Vesting terms				The earlier of: the date on which it is determined if the performance goal has been achieved; or, March 31, 2018.
Performance Shares [Member] | Employee Stock Plan [Member] | Date Twenty Three [Member] | At The End of Period [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted		14,400
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	[1]	$ 63.10
Vesting terms		The earlier of: the date on which it is determined if the performance goal has been achieved; or, March 31, 2020.

[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.

[2] This restricted stock grant fully vested upon an employee's termination, on November 30, 2017.

[3] These restricted stock grants will vest at the end of a five year period, or earlier if the director ceases to be a director for any reason other than cause, such as, for example, by retirement.

[4] These restricted stock grants will vest on May 24, 2021, or earlier if the director ceases to be a director for any reason other than cause, such as, for example, by retirement.

[5] These restricted stock grants will vest on May 27, 2020, or earlier if the director ceases to be a director for any reason other than cause, such as, for example, by retirement.