Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Stockholders' Equity [Abstract]
Issuance of restricted stock, stock incentive plan, shares	14,363	14,009	13,699
Stock options exercised, shares	0	927	3,872
Issuance of common stock, dividend investment plan, shares	32,340	31,904	30,627
Issuance of common stock, employee benefit plan, shares	8,030	8,893	8,560
Dividends declared, per share (in USD per share)	$ 0.80	$ 0.77	$ 0.76