Common Stock (Tables)

12 Months Ended

Dec. 31, 2011

Common Stock [Abstract]

Summary Of Components Used To Calculate Basic And Diluted Income Per Share

(In thousands, except per share data)	2011		2010		2009
Basic income per common share:
Net income attributable to Commerce Bancshares, Inc.	$	256,343	$	221,710	$	169,075
Less income allocated to nonvested restricted stockholders	1,846		1,208		741
Net income available to common stockholders	$	254,497	$	220,502	$	168,334
Distributed income	$	78,556	$	77,796	$	74,384
Undistributed income	$	175,941	$	142,706	$	93,950
Weighted average common shares outstanding	89,874		91,326		89,478
Distributed income per share	$	.87	$	.85	$	.83
Undistributed income per share	1.96		1.56		1.05
Basic income per common share	$	2.83	$	2.41	$	1.88
Diluted income per common share:
Net income attributable to Commerce Bancshares, Inc.	$	256,343	$	221,710	$	169,075
Less income allocated to nonvested restricted stockholders	1,842		1,204		740
Net income available to common stockholders	$	254,501	$	220,506	$	168,335
Distributed income	$	78,556	$	77,796	$	74,384
Undistributed income	$	175,945	$	142,710	$	93,951
Weighted average common shares outstanding	89,874		91,326		89,478
Net effect of the assumed exercise of stock-based awards -- based on the treasury stock method using the average market price for the respective periods	328		425		351
Weighted average diluted common shares outstanding	90,202		91,751		89,829
Distributed income per share	$	.87	$	.85	$	.83
Undistributed income per share	1.95		1.55		1.04
Diluted income per common share	$	2.82	$	2.40	$	1.87

Schedule Of Activity In The Outstanding Shares Of The Company's Common Stock

	Years Ended December 31
(In thousands)	2011		2010		2009
Shares outstanding at January 1	86,624		83,008		75,791
Issuance of stock:
Awards and sales under employee and director plans	724		603		394
Stock offering	—		—		2,895
5% stock dividend	4,231		4,122		3,949
Purchases of treasury stock	(2,622	)	(1,103	)	(16	)
Other	(5	)	(6	)	(5	)
Shares outstanding at December 31	88,952		86,624		83,008