Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 166,249	$ 38,731	$ 299,478	$ 88,334
Other comprehensive income (loss)
Net unrealized gains (losses) on available for sale debt securities	55,725	86,462	(102,951)	165,134
Pension loss amortization	438	355	875	711
Unrealized gains (losses) on cash flow hedge derivatives	(4,525)	9,308	(8,911)	72,972
Current period other comprehensive income (loss), net of tax	51,638	96,125	(110,987)	238,817
Comprehensive income	217,887	134,856	188,491	327,151
Less non-controlling interest expense (income)	3,923	(1,132)	6,180	(3,386)
Comprehensive income attributable to Commerce Bancshares, Inc.	$ 213,964	$ 135,988	$ 182,311	$ 330,537