Share-Based Payments (Tables)

3 Months Ended

Mar. 31, 2020

Share-based Payment Arrangement [Abstract]

Schedule of Nonvested Share Activity [Table Text Block]

	Number of Shares			Weighted Average Grant-Date Fair Value
Nonvested options – beginning of period		514,210		$	12.36
Nonvested options granted		9,000		$	12.16
Nonvested options vested or forfeited		(10,180	)	$	10.10
Nonvested options – end of period		513,030		$	12.40

Share-based Payment Arrangement, Option, Activity [Table Text Block]

	Shares			Weighted Average Exercise Price
Outstanding at January 1, 2020		815,800		$	49.89
Options granted		9,000			69.11
Options forfeited		(2,140	)		57.03
Options exercised		(18,940	)		33.82
Outstanding at March 31, 2020		803,720			$ 50. 46
Options exercisable		290,690		$	35.09
Options available for future grants		566,835

Cash Proceeds Received and Tax Benefit from Share-based Payment Awards [Table Text Block]

(In thousands)	March 31, 2020		March 31, 2019
Cash proceeds from stock options exercised	$	641	$	2,251
Tax benefits		—		300
Intrinsic value of stock options exercised		733		2,226

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

	March 31, 2020			March 31, 2019
Weighted average expected stock-price volatility		25	%		27	%
Weighted average expected option life		5 years			5 years
Weighted average risk-free interest rate		1.4	%		2.5	%
Weighted average dividend yield		2.5	%		2.0	%