Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 65,900	$ 66,039	$ 130,021	$ 126,847
Other comprehensive income (loss)
Net unrealized gains (losses) on securities for which a portion of an other-than-temporary impairment has been recorded in earnings	(58)	(120)	108	1,017
Net unrealized gains (losses) on other securities	43,650	(108,254)	74,029	(116,447)
Pension loss amortization	223	475	446	950
Other comprehensive income	43,815	(107,899)	74,583	(114,480)
Comprehensive income	109,715	(41,860)	204,604	12,367
Non-controlling interest expense	(631)	234	(823)	25
Comprehensive income attributable to Commerce Bancshares, Inc	$ 110,346	$ (42,094)	$ 205,427	$ 12,342