Acquired Loans - Schedule of Covered and Noncovered Acquired Loans by Type (Details) - USD ($) $ in Thousands	Sep. 30, 2016		Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	$ 295,737			$ 390,411
Less allowance for loan losses, acquired loans	11,380		$ 12,480	11,992	$ 12,185	$ 12,629	$ 12,059
Noncovered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	291,825			372,711
Less allowance for loan losses, acquired loans	11,330		12,218	11,259	11,417	11,927	10,541
Net acquired loans	280,495			361,452
Covered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	3,912	[1]		17,700
Less allowance for loan losses, acquired loans	50	[1]	$ 262	733	$ 768	$ 702	$ 1,518
Net acquired loans	3,862	[1]		16,967
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member] | Noncovered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	25,040			41,623
Construction, Land Development and Other Land [Member] | Loans Secured by Real Estate [Member] | Covered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	0	[1]		1,021
Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member] | Noncovered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	72,689			86,950
Secured by 1-4 Family Residential Properties [Member] | Loans Secured by Real Estate [Member] | Covered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	3,912	[1]		10,058
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member] | Noncovered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	110,606			135,626
Secured by Nonfarm, Nonresidential Properties [Member] | Loans Secured by Real Estate [Member] | Covered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	0	[1]		4,638
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member] | Noncovered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	20,903			23,860
Other Real Estate Secured [Member] | Loans Secured by Real Estate [Member] | Covered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	0	[1]		1,286
Commercial and Industrial Loans [Member] | Noncovered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	39,519			55,075
Commercial and Industrial Loans [Member] | Covered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	0	[1]		624
Consumer Loans [Member] | Noncovered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	3,878			5,641
Consumer Loans [Member] | Covered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	0	[1]		0
Other Loans [Member] | Noncovered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	19,190			23,936
Other Loans [Member] | Covered Loans [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Acquired loans	$ 0	[1]		$ 73

[1] Trustmark’s loss share agreement with the FDIC covering the acquired covered loans other than loans secured by 1-4 family residential properties expired on June 30, 2016. Trustmark’s loss share agreement with the FDIC covering the acquired covered loans secured by 1-4 family residential properties will expire in 2021. Effective July 1, 2016, all acquired covered loans excluding the acquired covered loans secured by 1-4 family residential properties were reclassified to acquired noncovered loans.