CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY AND COMPREHENSIVE INCOME (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY AND COMPREHENSIVE INCOME [Abstract]
Cash dividends declared (in dollars per share)	$ 1.00	$ 1.00	$ 1.00
Distribution of shares of treasury stock for directors' compensation (in shares)	10,378	10,082	10,867
Distribution of shares of treasury stock for directors' deferred compensation (in shares)	286	25,443	1,333
Distribution of shares of treasury stock for employee compensation (in shares)	2,392	2,750	2,381
Sale of shares of treasury stock (in shares)	9,500	6,000	11,800
Purchase of shares of treasury stock (in shares)	21,426	20,260	7,778
Distribution of shares of treasury stock granted for employee restricted stock awards (in shares)	8,834	5,886
Forfeit of shares of restricted stock awards (in shares)	1,087
Issuance of shares related to FOFC Merger (in shares)	1,009,942