Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total		Common Stock	Additional Paid-In Capital	Retained Earnings		Unallocated ESOP Shares	Accumulated Other Comprehensive Income (Loss)	Treasury Stock
Stockholders' Equity, Beginning Balance at Dec. 31, 2015	$ 213,971		$ 17,421	$ 250,680	$ 32,139		$ (1,100)	$ (7,972)	$ (77,197)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	6,549				6,549
Other Comprehensive Income	2,536	[1]						2,536
Cash Dividends Paid	(3,239)				(3,239)	[2]
Stock Options Exercised, Net	547			320					227
Shares Issued Under the Employee Stock Purchase Plan	112			69					43
Shares Issued for Dividend Reinvestment Plans	438			275					163
Stock-Based Compensation Expense	74			74
Tax Benefit for Disposition of Stock Options	21			21
Purchases of Treasury Stock	(527)								(527)
Allocation of ESOP Stock	221			71			150
Stockholders' Equity, Ending Balance at Mar. 31, 2016	220,703		17,421	251,510	35,449		(950)	(5,436)	(77,291)
Stockholders' Equity, Beginning Balance at Dec. 31, 2016	232,852		17,943	270,880	28,644		(400)	(6,834)	(77,381)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	6,631				6,631
Other Comprehensive Income	154	[1]						154
Cash Dividends Paid	(3,374)				(3,374)
Stock Options Exercised, Net	388			187					201
Shares Issued Under the Directors' Stock Plan	22			14					8
Shares Issued Under the Employee Stock Purchase Plan	106			69					37
Shares Issued for Dividend Reinvestment Plans	425			284					141
Stock-Based Compensation Expense	83			83
Purchases of Treasury Stock	(1,176)								(1,176)
Stockholders' Equity, Ending Balance at Mar. 31, 2017	$ 236,111		$ 17,943	$ 271,517	$ 31,901		$ (400)	$ (6,680)	$ (78,170)

[1] These accumulated other comprehensive income components are included in the computation of net periodic pension cost.

[2] Cash dividends paid per share have been adjusted for the September 29, 2016 3.0% stock dividend.