Consolidated Statements of Changes in Stockholders’ Equity (Unaudited) (Parentheticals) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Issuance upon exercise of stock options, common shares	52,320
Cash dividends declared and paid on common shares, per common share (in Dollars per share)	$ 0.13	$ 0.13
Reclassification adjustment for gains included in net income, tax effect (in Dollars)	$ (1,249)
Additional Paid-in Capital [Member]
Award of common shares released from Employee Benefit Trust, common shares	133,656	146,735
Shares issued upon vesting of restricted stock unit awards, common shares	98,610	85,163
Issuance upon exercise of stock options, common shares	42,400	56,850
Treasury Stock [Member] | Outstanding Common Shares Repurchased [Member]
Repurchase of outstanding shares, common shares	18,560	97,200
Treasury Stock [Member] | Shares Repurchased To Fund Options Exercised [Member]
Repurchase of outstanding shares, common shares	39,957	40,866
Treasury Stock [Member] | Shares Repurchased To Satisfy Tax Obligations [Member]
Repurchase of outstanding shares, common shares	42,666	27,883
Treasury Stock [Member]
Shares issued upon vesting of restricted stock unit awards, common shares	151,652	113,993
Issuance upon exercise of stock options, common shares	52,320	67,330
Retained Earnings [Member]
Shares issued upon vesting of restricted stock unit awards, common shares	53,042	28,830
Issuance upon exercise of stock options, common shares	9,920	10,480
Cash dividends declared and paid on common shares, per common share (in Dollars per share)	$ 0.13	$ 0.13
Accumulated Other Comprehensive Income (Loss) [Member]
Change in net unrealized gains (losses) on securities available for sale, tax effect (in Dollars)	2,013	(962)
Amortization of actuarial losses, tax effect (in Dollars)	(135)	(117)
Amortization of prior service credits, tax effect (in Dollars)	5	5
Reclassification adjustment for gains included in net income, tax effect (in Dollars)	$ 1,249