Shared-Based Compensation And Share Repurchase Plans (Tables)

12 Months Ended

Dec. 31, 2018

Shared-Based Compensation And Share Repurchase Plans [Abstract]

Schedule Of Fair Value Of Options, Weighted Average Assumptions

	2018		2017		2016
Stock option exercise price	$	16.40	$	15.94	$	11.87
Risk-free interest rate		2.56%		1.66%		1.20%
Expected dividend yield		—		—		—
Expected option life in years		3.75		3.75		3.75
Expected volatility		24.99%		24.95%		25.01%
Weighted average fair value	$	3.80	$	3.45	$	2.49

Schedule Of Stock Options Outstanding And Exercisable

	Outstanding Stock Options
	Number of Options		Weighted Average Exercise Price				Weighted Average Remaining Years of Contractual Life	Aggregate Intrinsic Value
	Class A	Class B	Class A		Class B		Class A&B	Class A&B
Outstanding - January 1, 2016	486,565	—	$	8.68	$	—	2.89	$	2,188,011
Granted	169,327	—		11.87		—
Exercised	(46,815)	—		9.50		—			220,002
Expired	(74,000)	—		7.02		—
Outstanding - December 31, 2016	535,077	—	$	9.84	$	—	2.61	$	3,615,191
Granted	169,762	—		15.94		—
Exercised	(177,750)	—		7.85		—			702,840
Expired	(2,500)	—		6.23		—
Outstanding - December 31, 2017	524,589	—	$	12.50	$	—	3.15	$	3,054,325
Granted	126,840	—		16.40		—
Exercised	(60,000)	—		6.02		—			610,249
Expired	(4,960)	—		12.08		—
Outstanding - December 31, 2018	586,469	—	$	14.01	$	—	2.88	$	1,530,528

Schedule Of Vested And Unvested Stock Options

	Vested and Unvested Stock Options
	Number of Options		Weighted Average Exercise Price				Weighted Average Remaining Years of Contractual Life	Aggregate Intrinsic Value
	Class A	Class B	Class A			Class B	Class A&B	Class A&B
Vested
December 31, 2018	231,124	—	$	12.38	$	—	2.28	$	1,306,643
December 31, 2017	186,832	—		9.84		—	2.30		2,202,772
December 31, 2016	296,500	—		7.88		—	1.59		2,584,500
Unvested
December 31, 2018	355,345	—	$	15.07	$	—	3.27	$	223,885
December 31, 2017	337,757	—		13.86		—	3.62		851,552
December 31, 2016	238,577	—		12.28		—	3.87		1,030,691

Schedule Of Restricted Stock Units Issued And Vested

	Number of RSUs				$ value of RSUs
	Granted	Vesting	Unvested	Granted		Vesting		Unvested
2016	68,153	51,650	16,503	$	815,160	$	613,208	$	201,952
2017	70,538	40,645	29,893		1,124,348		648,569		475,779
2018	97,600	—	97,600		1,567,171		—		1,567,171
Total	236,291	92,295	143,996	$	3,506,679	$	1,261,777	$	2,244,902