Note 5 - Reconciliation of Common Shareholders' Equity, Common Shares and Earnings Per Share (Tables)

3 Months Ended

Mar. 31, 2018

Notes Tables

Schedule of Stockholders Equity [Table Text Block]

(in thousands)	Par Value, Common Shares			Premium on Common Shares			Retained Earnings			Accumulated Other Comprehensive Loss			Total Common Equity
Balance, December 31, 2017	$	197,787		$	343,450		$	161,286		$	(5,631	)	$	696,892
Common Stock Issuances, Net of Expenses		638			(638	)								--
Common Stock Retirements		(292	)		(2,117	)								(2,409	)
Net Income								26,215						26,215
Other Comprehensive Loss											(502	)		(502	)
Employee Stock Incentive Plans Expense					1,146									1,146
Common Dividends ($0.335 per share)								(13,292	)					(13,292	)
Balance, March 31, 2018	$	198,133		$	341,841		$	174,209		$	(6,133	)	$	708,050

Schedule of Common Stock Outstanding Roll Forward [Table Text Block]

Common Shares Outstanding, December 31, 2017	39,557,491
Issuances:
Executive Stock Performance Awards (2015 shares earned)	114,648
Vesting of Restricted Stock Units	12,950
Retirements:
Shares Withheld for Individual Income Tax Requirements	(58,495	)
Common Shares Outstanding, March 31, 2018	39,626,594

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	2018		2017
Weighted Average Common Shares Outstanding – Basic		39,550,874		39,350,802
Plus Outstanding Share Awards net of Share Reductions for Unrecognized Stock-Based Compensation Expense and Excess Tax Benefits:
Shares Expected to be Awarded for Stock Performance Awards Granted to Executive Officers based on Measurement Period-to-Date Performance		223,162		201,639
Underlying Shares Related to Nonvested Restricted Stock Units Granted to Employees		59,130		57,873
Nonvested Restricted Shares		27,643		27,069
Shares Expected to be Issued Under the Deferred Compensation Program for Directors		2,873		3,342
Total Dilutive Shares		312,808		289,923
Weighted Average Common Shares Outstanding – Diluted		39,863,682		39,640,725