Share-Based Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2019

Share-Based Compensation Plans [Abstract]

Company's Shareholder Approved Plans

				Weighted-
		Weighted-		Average
		Average		Remaining	Aggregate
(Aggregate Intrinsic Value in thousands)		Exercise		Contractual	Intrinsic
Options	Shares	Price/Share		Term	Value
Outstanding at January 1, 2019	279,164	$	83.84
Granted	–		-
Exercised	108,460		78.58
Forfeited/Cancelled/Expired	–		-
Outstanding at December 31, 2019	170,704		87.18	1.4	$	32,376
			.
Exercisable at December 31, 2019	170,704		87.18	1.4	$	32,376

				Weighted-
		Weighted-		Average
		Average		Remaining	Aggregate
(Aggregate Intrinsic Value in thousands)		Exercise		Contractual	Intrinsic
Options	Shares	Price/Share		Term	Value
Outstanding at January 1, 2018	360,364	$	84.10
Granted	-		-
Exercised	81,200		84.99
Forfeited/Cancelled/Expired	-		-
Outstanding at December 31, 2018	279,164		83.84	1.9	$	37,386
Exercisable at December 31, 2018	279,164		83.84	1.9	$	37,386

				Weighted-
		Weighted-		Average
		Average		Remaining	Aggregate
(Aggregate Intrinsic Value in thousands)		Exercise		Contractual	Intrinsic
Options	Shares	Price/Share		Term	Value
Outstanding at January 1, 2017	454,994	$	84.88
Granted	-		-
Exercised	94,630		87.84
Forfeited/Cancelled/Expired	-		-
Outstanding at December 31, 2017	360,364		84.10	2.7	$	49,428
Exercisable at December 31, 2017	360,364		84.10	2.7	$	49,428

Share Options Outstanding And Exercisable

	At December 31, 2019
	Options Outstanding				Opotions Exercisable
		Weighted-
		Average	Weighted-			Weighted-
	Number	Remaining	Average		Number	Average
Range of	Outstanding	Contractual	Exercise		Exercisable	Exercise
Exercise Prices	at 12/31/19	Life	Price		at 12/31/19	Price
$84.6300 - $85.6300	31,100	0.2	$	84.63	31,100	$	84.63
$85.6400 - $87.4700	59,900	1.2		86.62	59,900		86.62
$87.4800 - $89.4100	73,750	2.1		88.32	73,750		88.32
$89.4200 - $110.1300	5,954	1.5		91.99	5,954		91.99
	170,704	1.4		87.18	170,704		87.18

Summary Of Company's Non-Vested Shares And Changes

	Years Ended December 31,
	2019			2018			2017
		Weighted-			Weighted-			Weighted-
		Average			Average			Average
		Grant Date			Grant Date			Grant Date
Restricted (non-vested) Shares	Shares	Fair Value		Shares	Fair Value		Shares	Fair Value
Outstanding at January 1,	414,407	$	217.15	421,261	$	194.01	435,338	$	164.21
Granted	232,601		-	173,065		240.59	160,185		234.01
Vested	138,322		-	141,982		178.31	152,397		151.80
Forfeited	13,549		-	37,937		212.48	21,865		187.82
Outstanding at December 31,	495,137		-	414,407		217.15	421,261		194.01

Company's Non-Vested Performance Share Unit Awards

	Years Ended December 31,
	2019			2018			2017
		Weighted-			Weighted-			Weighted-
		Average			Average			Average
		Grant Date			Grant Date			Grant Date
Performance Share Unit Awards	Shares	Fair Value		Shares	Fair Value		Shares	Fair Value
Outstanding at January 1,	32,382	$	-	33,454	$	-	21,223	$	-
Granted	16,855		223.45	13,325		242.39	11,245		234.03
Increase/(Decrease) on vesting units due to performance	(3,455)		-	(267)		-	986		-
Vested	10,922		223.45	12,435		242.39	-		-
Forfeited	-		-	1,695		-	-		-
Outstanding at December 31,	34,850		-	32,382		-	33,454		-