Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 102,061	$ 71,702
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	45	95
Net unrealized gains (losses) on other securities	(73,721)	19,002
Pension loss amortization	393	340
Other comprehensive income (loss), net of tax	(73,283)	19,437
Comprehensive income	28,778	91,139
Non-controlling interest expense (income)	1,077	198
Comprehensive income attributable to Commerce Bancshares, Inc	$ 27,701	$ 90,941