Common Stock (Tables)

12 Months Ended

Dec. 31, 2012

Common Stock, Number of Shares, Par Value and Other Disclosures [Abstract]

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

(In thousands, except per share data)	2012		2011		2010
Basic income per common share:
Net income attributable to Commerce Bancshares, Inc.	$	269,329	$	256,343	$	221,710
Less income allocated to nonvested restricted stockholders	2,563		1,846		1,208
Net income available to common stockholders	$	266,766	$	254,497	$	220,502
Weighted average common shares outstanding	91,614		94,368		95,893
Basic income per common share	$	2.91	$	2.70	$	2.30
Diluted income per common share:
Net income attributable to Commerce Bancshares, Inc.	$	269,329	$	256,343	$	221,710
Less income allocated to nonvested restricted stockholders	2,562		1,842		1,204
Net income available to common stockholders	$	266,767	$	254,501	$	220,506
Weighted average common shares outstanding	91,614		94,368		95,893
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	280		344		446
Weighted average diluted common shares outstanding	91,894		94,712		96,339
Diluted income per common share	$	2.90	$	2.69	$	2.29

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

The table below shows activity in the outstanding shares of the Company’s common stock during the past three years. Shares in the table below are presented on an historical basis and have not been restated for the annual 5% stock dividends.

	Years Ended December 31
(In thousands)	2012		2011		2010
Shares outstanding at January 1	88,952		86,624		83,008
Issuance of stock:
Awards and sales under employee and director plans	837		724		603
5% stock dividend	4,352		4,231		4,122
Purchases of treasury stock	(2,716	)	(2,622	)	(1,103	)
Other	(11	)	(5	)	(6	)
Shares outstanding at December 31	91,414		88,952		86,624