Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 97,055	$ 102,061
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	41	45
Net unrealized gains (losses) on other securities	73,441	(73,721)
Pension loss amortization	389	393
Unrealized losses on cash flow hedge derivatives	2,779	0
Other comprehensive income (loss), net of tax	76,650	(73,283)
Comprehensive income	173,705	28,778
Non-controlling interest expense (income)	(83)	1,077
Comprehensive income attributable to Commerce Bancshares, Inc	$ 173,788	$ 27,701