PENSION, OTHER POST RETIREMENT BENEFIT AND PROFIT SHARING PLANS (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Benefits as a percentage of cash balance	2.50%
Pension Benefits [Member]
Change in benefit obligations:
Projected benefit obligations at beginning of year	$ 201,696,000	$ 213,804,000	$ 182,362,000
Service cost	8,936,000	10,735,000	9,670,000
Interest cost	9,358,000	8,212,000	8,104,000
Amendments		10,850,000	300,000
Actuarial loss	53,131,000	(18,794,000)	22,417,000
Benefits paid	(9,029,000)	(22,116,000)	(8,232,000)
Administrative expenses paid	(595,000)	(995,000)	(817,000)
Projected benefit obligations at end of year	263,497,000	201,696,000	213,804,000
Change in plans' assets:
Fair value of plans assets at beginning of year	196,447,000	203,704,000	195,004,000
Actual return on assets	12,525,000	13,960,000	16,631,000
Employer contributions	2,004,000	1,894,000	1,118,000
Benefits paid	(9,029,000)	(22,116,000)	(8,232,000)
Administrative expenses paid	(595,000)	(995,000)	(817,000)
Fair value of plans assets at end of year	201,352,000	196,447,000	203,704,000
Funded status:
Projected benefit obligations	(263,497,000)	(201,696,000)	(213,804,000)
Fair value of plans assets	201,352,000	196,447,000	203,704,000
Net amount recognized	(62,145,000)	(5,249,000)	(10,100,000)
Amounts recognized in the consolidated balance sheets consisted of:
Prepaid benefit cost	64,838,000	72,886,000	94,046,000
Accrued benefit liability	(23,902,000)	(23,241,000)	(22,123,000)
Intangible asset
Accumulated other comprehensive income adjustment	(103,081,000)	(54,894,000)	(82,023,000)
Net amount recognized	(62,145,000)	(5,249,000)	(10,100,000)
Pre-tax amounts recognized in accumulated other comprehensive income consisted of:
Net transition obligation		19,000
Net prior service (benefit) cost	(4,598,000)	(5,366,000)
Net actuarial loss	107,679,000	60,241,000
Total accumulated other comprehensive income	103,081,000	54,894,000	82,023,000
Net transition obligation that will be amortized into net periodic cost over the next fiscal year	(718,000)
Recognized prior service (benefit) cost	(768,000)	(768,000)	(768,000)
Net actuarial loss that will be amortized into net periodic cost over the next fiscal year	7,900,000
Components of net periodic benefit cost:
Service cost	8,936,000	10,735,000	9,670,000
Interest cost	9,358,000	8,212,000	8,104,000
Expected return on assets	(10,534,000)	(10,974,000)	(11,263,000)
Amortization of unrecognized transition amount	18,000	18,000	18,000
Recognized prior service (benefit) cost	(768,000)	(768,000)	(768,000)
Recognized net loss	3,702,000	6,099,000	4,868,000
Special termination benefit		10,850,000	300,000
Net periodic benefit cost	10,712,000	24,172,000	10,929,000
Basic Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
General information	The Basic Plan is a non-contributory defined benefit pension plan managed by a trustee covering substantially all full-time employees who have at least one year of service and have attained the age of 21. For such employees hired prior to January 1, 2006, benefits are based on years of service and the employee's compensation
Benefits as a percentage of cash balance	2.50%
Weighted-average assumptions used to determine benefit obligation [Abstract]
Discount rate (in hundredths)	4.10%	4.90%
Rate of compensation increase (in hundredths)	3.00%	3.00%
Weighted-average assumptions used to determine net periodic benefit cost [Abstract]
Discount rate (in hundredths)	4.90%	4.05%	4.80%
Rate of compensation increase (in hundredths)	3.00%	3.00%	3.00%
Expected rate of return on plan assets (in hundredths)	5.50%	5.50%	6.00%
Restoration Plan and Supplemental Plan [Member]
Accumulated benefit obligations in excess of plan assets [Abstract]
Projected benefit obligation	263,497,000	31,512,000
Accumulated benefit obligation	252,227,000	29,191,000
Fair value of assets	201,352,000
Restoration Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
General information	The Restoration Plan provides for the payment of retirement benefits to certain participants in the Basic Plan.
Weighted-average assumptions used to determine benefit obligation [Abstract]
Discount rate (in hundredths)	3.90%	4.50%
Rate of compensation increase (in hundredths)	3.00%	3.00%
Weighted-average assumptions used to determine net periodic benefit cost [Abstract]
Discount rate (in hundredths)	4.50%	3.65%	4.45%
Rate of compensation increase (in hundredths)	3.00%	3.00%	3.00%
Supplemental Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
General information	The Supplemental Plan is a non-qualified defined benefit supplemental retirement plan for certain key employees. Benefits commence when the employee retires and are payable over a period of ten years.
Period after employee retirement during which benefits are payable	10 years
Weighted-average assumptions used to determine benefit obligation [Abstract]
Discount rate (in hundredths)	3.10%	3.65%
Rate of compensation increase (in hundredths)	3.00%	3.00%
Weighted-average assumptions used to determine net periodic benefit cost [Abstract]
Discount rate (in hundredths)	3.65%	2.85%	3.85%
Rate of compensation increase (in hundredths)	3.00%	3.00%	3.00%
BancorpSouth, Inc. (Parent Company Only) [Member] | Basic Plan [Member]
Change in plans' assets:
Fair value of plans assets at end of year	1,900,000	2,100,000
Funded status:
Fair value of plans assets	$ 1,900,000	$ 2,100,000