Stock-Based Compensation Plans (Tables)

6 Months Ended

Jun. 30, 2018

A summary of the Company's stock option activity for the six months ended June 30, 2018 and June 30, 2017 is presented below:



Stock Options	Common Shares		Weighted Average Strike Price		Remaining Contractual Term⁽¹⁾	Intrinsic Value ⁽²⁾ ($000)
Outstanding at January 1, 2018	1,084,756		$	41.98
Granted	—		—
Exercised	(231,902	)	41.65
Forfeited or canceled	(4,361	)	40.87
Outstanding at June 30, 2018	848,493		$	42.07	3.5	$	38,164
Exercisable at June 30, 2018	650,494		$	42.24	3.2	$	29,147



Stock Options	Common Shares		Weighted Average Strike Price		Remaining Contractual Term ⁽¹⁾	Intrinsic Value ⁽²⁾ ($000)
Outstanding at January 1, 2017	1,698,912		$	41.50
Granted	—		—
Exercised	(374,046	)	40.28
Forfeited or canceled	(8,173	)	42.49
Outstanding at June 30, 2017	1,316,693		$	41.84	4.4	$	45,561
Exercisable at June 30, 2017	765,711		$	41.56	3.7	$	26,707


(1)	Represents the remaining weighted average contractual life in years.

(2)

Aggregate intrinsic value represents the total pre-tax intrinsic value (i.e., the difference between the Company's stock price on the last trading day of the quarter and the option exercise price, multiplied by the number of shares) that would have been received by the option holders if they had exercised their options on the last day of the quarter. Options with exercise prices above the stock price on the last trading day of the quarter are excluded from the calculation of intrinsic value. The intrinsic value will change based on the fair market value of the Company's stock.

Summary Of Plans' Restricted Share And Performance-Vested Stock Award Activity

A summary of the Plans' restricted share activity for the six months ended June 30, 2018 and June 30, 2017 is presented below:



	Six months ended June 30, 2018				Six months ended June 30, 2017
Restricted Shares	Common Shares		Weighted Average Grant-Date Fair Value		Common Shares		Weighted Average Grant-Date Fair Value
Outstanding at January 1	127,787		$	53.33	133,425		$	49.94
Granted	24,888		87.44		13,385		72.36
Vested and issued	(9,725	)	56.33		(10,104	)	45.55
Forfeited or canceled	(982	)	55.39		—		—
Outstanding at June 30	141,968		$	59.09	136,706		$	52.46
Vested, but not issuable at June 30	90,105		$	51.80	89,391		$	51.55

A summary of the Plans' performance-based stock award activity, based on the target level of the awards, for the six months ended June 30, 2018 and June 30, 2017 is presented below:



	Six months ended June 30, 2018				Six months ended June 30, 2017
Performance-based Stock	Common Shares		Weighted Average Grant-Date Fair Value		Common Shares		Weighted Average Grant-Date Fair Value
Outstanding at January 1	359,196		$	54.37	298,180		$	43.64
Granted	129,479		88.26		143,439		72.55
Vested and issued	(82,307	)	44.39		(68,712	)	46.85
Forfeited	(10,343	)	56.28		(8,438	)	49.47
Outstanding at June 30	396,025		$	67.47	364,469		$	54.28
Vested, but deferred at June 30	21,432		$	43.32	13,590		$	42.60