Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 422,712	$ 438,214	$ 319,900
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	(632)	(277)	412
Net unrealized gains (losses) on other securities	151,122	(55,631)	3,022
Change in pension loss	1,167	664	(301)
Unrealized gain (loss) on cash flow hedge derivatives	23,456	6,855	0
Other comprehensive income (loss)	175,113	(48,389)	3,133
Comprehensive income	597,825	389,825	323,033
Non-controlling interest expense	1,481	4,672	517
Comprehensive income attributable to Commerce Bancshares, Inc.	$ 596,344	$ 385,153	$ 322,516