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]
Cash dividend per common share	$ 0.66	$ 0.64	$ 0.64
Stock Issued During Period, Shares, Restricted Stock Award, Gross	680,066	595,906	563,257
Treasury stock, shares, acquired	312,427	262,140	217,674
Stock Issued During Period, Shares, Treasury Stock Reissued	238,670	291,419	198,207
Stock Issued During Period, Shares, New Issues	0	0	55,468,283
Stock Repurchased During Period, Shares	2,571,998	0	2,408,203