Acquired Loans - Changes in the Carrying Value of Acquired Loans (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015
Carrying value of acquired loans [Abstract]
Accretion to interest income		$ 18,405		$ 30,501
Noncovered Loans [Member]
Carrying value of acquired loans [Abstract]
Carrying value, net, beginning		361,452
Carrying value, net, ending		257,321		361,452
Covered Loans [Member]
Carrying value of acquired loans [Abstract]
Carrying value, net, beginning		16,967
Carrying value, net, ending		3,529	[1]	16,967
Acquired Not ASC 310-30 [Member] | Noncovered Loans [Member]
Carrying value of acquired loans [Abstract]
Carrying value, net, beginning	[2]	66,086		81,091
Transfers	[2],[3]	446
Accretion to interest income	[2]	40		479
Payments received, net	[2]	(24,490)		(15,484)
Other	[2],[4]	0		0
Less change in allowance for loan losses, acquired loans	[2]	453		0
Carrying value, net, ending	[2]	42,535		66,086
Acquired Not ASC 310-30 [Member] | Covered Loans [Member]
Carrying value of acquired loans [Abstract]
Carrying value, net, beginning	[2]	1,571		1,604
Transfers	[2],[3]	(446)
Accretion to interest income	[2]	0		0
Payments received, net	[2]	(463)		(33)
Other	[2],[4]	0		0
Less change in allowance for loan losses, acquired loans	[2]	(454)		0
Carrying value, net, ending	[2]	208		1,571
Acquired Impaired [Member] | Noncovered Loans [Member]
Carrying value of acquired loans [Abstract]
Carrying value, net, beginning		295,366		434,151
Transfers	[3]	9,157
Accretion to interest income		17,475		28,193
Payments received, net		(107,013)		(164,671)
Other	[4]	307		(1,589)
Less change in allowance for loan losses, acquired loans		(506)		(718)
Carrying value, net, ending		214,786		295,366
Acquired Impaired [Member] | Covered Loans [Member]
Carrying value of acquired loans [Abstract]
Carrying value, net, beginning		15,396		20,504
Transfers	[3]	(9,157)
Accretion to interest income		930		2,308
Payments received, net		(4,509)		(8,592)
Other	[4]	(441)		391
Less change in allowance for loan losses, acquired loans		1,102		785
Carrying value, net, ending		$ 3,321		$ 15,396

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

[2] "Acquired Not ASC 310-30" loans consist of revolving credit agreements and commercial leases that are not in scope for FASB ASC Topic 310-30.

[3] Acquired covered loans transferred to acquired noncovered loans as a result of the expiration of the related loss share agreement with the FDIC on June 30, 2016.

[4] Includes miscellaneous timing adjustments as well as acquired loan terminations through foreclosure, charge-off and other terminations.