Shareholders' Equity (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011 Trustmark Corporation [Member] Total Capital (to Risk Weighted Assets) [Member]		Dec. 31, 2010 Trustmark Corporation [Member] Total Capital (to Risk Weighted Assets) [Member]		Jun. 30, 2011 Trustmark Corporation [Member] Tier 1 Capital (to Risk Weighted Assets) [Member]		Dec. 31, 2010 Trustmark Corporation [Member] Tier 1 Capital (to Risk Weighted Assets) [Member]		Jun. 30, 2011 Trustmark Corporation [Member] Tier 1 Capital (to Average Assets) [Member]		Dec. 31, 2010 Trustmark Corporation [Member] Tier 1 Capital (to Average Assets) [Member]		Jun. 30, 2011 Trustmark National Bank [Member] Total Capital (to Risk Weighted Assets) [Member]	Dec. 31, 2010 Trustmark National Bank [Member] Total Capital (to Risk Weighted Assets) [Member]	Jun. 30, 2011 Trustmark National Bank [Member] Tier 1 Capital (to Risk Weighted Assets) [Member]	Dec. 31, 2010 Trustmark National Bank [Member] Tier 1 Capital (to Risk Weighted Assets) [Member]	Jun. 30, 2011 Trustmark National Bank [Member] Tier 1 Capital (to Average Assets) [Member]	Dec. 31, 2010 Trustmark National Bank [Member] Tier 1 Capital (to Average Assets) [Member]
Total Capital (to Risk Weighted Assets) [Abstract]
Actual Regulatory Capital Amount			$ 1,080,092		$ 1,051,933										$ 1,042,010	$ 1,014,219
Actual Regulatory Capital Ratio (in hundredths)			16.47%		15.77%										16.09%	15.40%
Minimum Regulatory Capital Required Amount			524,535		533,774										518,140	526,894
Minimum Regulatory Capital Required Ratio (in hundredths)			8.00%		8.00%										8.00%	8.00%
Minimum Regulatory Provision to be Well-Capitalized Amount				[1]		[1]									647,675	658,617
Minimum Regulatory Provision to be Well-Capitalized Ratio (in hundredths)				[1]		[1]									10.00%	10.00%
Tier 1 Capital (to Risk Weighted Assets) [Abstract]
Actual Regulatory Capital Amount							948,250		918,600								912,559	883,549
Actual Regulatory Capital Ratio (in hundredths)							14.46%		13.77%								14.09%	13.42%
Minimum Regulatory Capital Required Amount							262,268		266,887								259,070	263,447
Minimum Regulatory Capital Required Ratio (in hundredths)							4.00%		4.00%								4.00%	4.00%
Minimum Regulatory Provision to be Well-Capitalized Amount								[1]		[1]							388,605	395,170
Minimum Regulatory Provision to be Well-Capitalized Ratio (in hundredths)								[1]		[1]							6.00%	6.00%
Tier 1 Capital (to Average Assets) [Abstract]
Actual Regulatory Capital Amount											948,250		918,600						912,559	883,549
Actual Regulatory Capital Ratio (in hundredths)											10.18%		10.14%						9.92%	9.89%
Minimum Regulatory Capital Required Amount											279,398		271,867						275,914	267,967
Minimum Regulatory Capital Required Ratio (in hundredths)											3.00%		3.00%						3.00%	3.00%
Minimum Regulatory Provision to be Well-Capitalized Amount												[1]		[1]					459,857	446,612
Minimum Regulatory Provision to be Well-Capitalized Ratio (in hundredths)												[1]		[1]					5.00%	5.00%
Other Comprehensive Income (Loss) before Tax [Abstract]
Accumulated other comprehensive income (loss), before tax	(18,469)	(2,596)
Unrealized Holding Gain (Loss) on Securities Arising During Period, before Tax	22,073	11,809
Reclassification Adjustment for Sale of Securities Included in Net Income, before Tax	(58)	(2,224)
Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax	2,439	1,796
Accumulated other comprehensive income (loss), before tax	5,985	8,785
Other Comprehensive Income (Loss), Tax [Abstract]
Accumulated other comprehensive income (loss), tax effect	7,043	972
Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax Effect	(8,443)	(4,517)
Reclassification Adjustment for Sale of Securities Included in Net Income, Tax Effect	22	851
Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Tax Effect	(933)	(687)
Accumulated other comprehensive income (loss), tax effect	(2,311)	(3,381)
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated Other Comprehensive Income (Loss), Net of Tax	(11,426)	(1,624)
Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	13,630	7,292
Reclassification Adjustment for Sale of Securities Included in Net Income, Net of Tax	(36)	(1,373)
Pension and Other Postretirement Benefit Plans, Net Unamortized (Gain) Loss Arising During Period, Net of Tax	1,506	1,109
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 3,674	$ 5,404

[1] n/a