Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 108,299	$ 111,324	$ 205,354	$ 213,385
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	(228)	(123)	(187)	(78)
Net unrealized gains (losses) on other securities	76,950	(19,489)	150,391	(93,210)
Pension loss amortization	388	394	777	787
Unrealized losses on cash flow hedge derivatives	19,807	0	22,586	0
Other comprehensive income (loss), net of tax	96,917	(19,218)	173,567	(92,501)
Comprehensive income	205,216	92,106	378,921	120,884
Non-controlling interest expense (income)	328	994	245	2,071
Comprehensive income attributable to Commerce Bancshares, Inc	$ 204,888	$ 91,112	$ 378,676	$ 118,813