Consolidated Statements Of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
INTEREST INCOME
Interest and fees on loans	$ 489,956	$ 456,664	$ 447,157
Interest and Fee Income, Loans and Leases Held-for-sale	1,317	191	0
Interest on investment securities	207,184	191,801	188,006
Interest Income, Federal Funds Sold and Securities Purchased under Agreements to Resell	78	60	101
Interest Income, Securities Purchased under Agreements to Resell	13,544	13,172	12,473
Interest on deposits with banks	973	528	555
Total interest income	713,052	662,416	648,292
INTEREST EXPENSE
Savings, interest checking and money market	14,366	13,374	13,522
Time open and C.D.’s of less than $100,000	2,809	3,236	4,137
Time open and C.D.’s of $100,000 and over	8,545	6,051	5,926
Interest on federal funds purchased and securities sold under agreements to repurchase	3,315	1,861	1,019
Interest on other borrowings	3,968	3,574	3,484
Total interest expense	33,003	28,096	28,088
Net interest income	680,049	634,320	620,204
Provision for loan losses	36,318	28,727	29,531
Net interest income after provision for loan losses	643,731	605,593	590,673
NON-INTEREST INCOME
Bank card transaction fees	181,879	178,926	175,806
Trust fees	121,795	118,437	111,254
Deposit account charges and other fees	86,394	80,416	78,680
Noninterest Income, Other	10,655	11,476	12,667
Capital market fees	13,784	13,784	12,534
Loan fees and sales	11,412	8,228	5,108
Other	48,473	36,872	40,457
Total non-interest income	474,392	448,139	436,506
INVESTMENT SECURITIES GAINS (LOSSES), NET
Investment securities gains (losses), net	(53)	6,320	14,124
NON-INTEREST EXPENSE
Salaries and employee benefits	427,310	400,701	384,100
Net occupancy	46,290	44,788	45,825
Equipment	19,141	19,086	18,375
Supplies and communication	24,135	22,970	22,432
Data processing and software	92,722	83,944	78,980
Marketing	16,032	16,107	15,676
Deposit insurance	13,327	12,146	11,622
Other	78,108	76,745	79,860
Total non-interest expense	717,065	676,487	656,870
Income before income taxes	401,005	383,565	384,433
Less income taxes	124,151	116,590	121,649
Net income	276,854	266,975	262,784
Less non-controlling interest expense	1,463	3,245	1,030
NET INCOME ATTRIBUTABLE TO COMMERCE BANCSHARES, INC.	275,391	263,730	261,754
Preferred Stock Dividends, Income Statement Impact	9,000	9,000	4,050
Net Income (Loss) Available to Common Stockholders, Basic	$ 266,391	$ 254,730	$ 257,704
Net income per common share - basic (in dollars per share)	$ 2.62	$ 2.44	$ 2.38
Net income per common share - diluted (in dollars per share)	$ 2.61	$ 2.43	$ 2.37