Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 38,731	$ 108,299	$ 88,334	$ 205,354
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	0	(228)	0	(187)
Net unrealized gains (losses) on other securities	86,462	76,950	165,134	150,391
Pension loss amortization	355	388	711	777
Unrealized gains (losses) on cash flow hedge derivatives	9,308	19,807	72,972	22,586
Other comprehensive income (loss), net of tax	96,125	96,917	238,817	173,567
Comprehensive income	134,856	205,216	327,151	378,921
Non-controlling interest expense (income)	(1,132)	328	(3,386)	245
Comprehensive income attributable to Commerce Bancshares, Inc	$ 135,988	$ 204,888	$ 330,537	$ 378,676