Regulatory Matters (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($) banks	Dec. 31, 2016 USD ($)
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Amount available for dividend distribution without affecting capital adequacy requirements	$ 283,000
Maximum allowed percentage of loans issued to a single affiliate	10000.00%
Maximum allowed percentage of aggregate loans issued to all affiliate	20000.00%
Significant subidiaries | banks	4
Excess tier one risk based capital	$ 1,000,000	$ 1,000,000
Total Capital [Abstract]
Capital	$ 2,179,147	$ 2,074,526
Capital to risk weighted assets	13.00%	13.20%
Capital required for capital adequacy	$ 1,338,560	$ 1,255,292
Capital required for capital adequacy to risk weighted assets	8.00%	8.00%
Tier One Risk Based Capital [Abstract]
Tier one risk based capital	$ 1,737,060	$ 1,637,150
Tier one risk based capital to risk weighted assets	10.40%	10.40%
Tier one risk based capital required for capital adequacy	$ 1,003,920	$ 941,469
Tier one risk based capital required for capital adequacy to risk weighted assets	6.00%	6.00%
CommonEquityTierOneCapitalAbstract [Abstract]
Common equity tier 1 capital	$ 1,737,060	$ 1,637,150
Common equity tier one capital ratio	10.40%	10.40%
Common equity tier one capital required for capital adequacy	$ 752,940	$ 706,102
Common equity tier one capital required for capital adequacy to risk weighted assets	4.50%	4.50%
Tier One Leverage Capital [Abstract]
Tier one leverage capital	$ 1,737,060	$ 1,637,150
Tier one leverage capital to average assets	8.90%	9.00%
Tier one leverage capital required for capital adequacy	$ 778,451	$ 727,745
Tier one leverage capital required for capital adequacy to average assets	4.00%	4.00%
Fulton Bank, N.A.
Total Capital [Abstract]
Capital	$ 1,234,536	$ 1,142,326
Capital to risk weighted assets	12.30%	12.20%
Capital required for capital adequacy	$ 805,125	$ 747,359
Capital required for capital adequacy to risk weighted assets	8.00%	8.00%
Capital required to be well capitalized	$ 1,006,406	$ 934,199
Capital required to be well capitalized to risk weighted assets	10.00%	10.00%
Tier One Risk Based Capital [Abstract]
Tier one risk based capital	$ 1,142,230	$ 1,050,175
Tier one risk based capital to risk weighted assets	11.30%	11.20%
Tier one risk based capital required for capital adequacy	$ 603,843	$ 560,519
Tier one risk based capital required for capital adequacy to risk weighted assets	6.00%	6.00%
Tier one risk based capital required to be well capitalized	$ 805,125	$ 747,359
Tier one risk based capital required to be well capitalized to risk weighted assets	8.00%	8.00%
CommonEquityTierOneCapitalAbstract [Abstract]
Common equity tier 1 capital	$ 1,098,230	$ 1,006,175
Common equity tier one capital ratio	10.90%	10.80%
Common equity tier one capital required for capital adequacy	$ 452,883	$ 420,389
Common equity tier one capital required for capital adequacy to risk weighted assets	4.50%	4.50%
Common equity tier one capital required to be well-capitalized	$ 654,164	$ 607,229
Common equity tier one capital required to be well capitalized to risk weighted assets	6.50%	6.50%
Tier One Leverage Capital [Abstract]
Tier one leverage capital	$ 1,142,230	$ 1,050,175
Tier one leverage capital to average assets	10.00%	10.10%
Tier one leverage capital required for capital adequacy	$ 458,016	$ 415,981
Tier one leverage capital required for capital adequacy to average assets	4.00%	4.00%
Tier one leverage capital required to be well capitalized	$ 572,520	$ 519,977
Tier one leverage capital required to be well capitalized to average assets	5.00%	5.00%
Fulton Bank of New Jersey
Total Capital [Abstract]
Capital	$ 385,858	$ 385,807
Capital to risk weighted assets	12.40%	13.10%
Capital required for capital adequacy	$ 248,640	$ 234,782
Capital required for capital adequacy to risk weighted assets	8.00%	8.00%
Capital required to be well capitalized	$ 310,801	$ 293,427
Capital required to be well capitalized to risk weighted assets	10.00%	10.00%
Tier One Risk Based Capital [Abstract]
Tier one risk based capital	$ 346,867	$ 348,992
Tier one risk based capital to risk weighted assets	11.20%	11.90%
Tier one risk based capital required for capital adequacy	$ 186,480	$ 176,086
Tier one risk based capital required for capital adequacy to risk weighted assets	6.00%	6.00%
Tier one risk based capital required to be well capitalized	$ 248,640	$ 234,782
Tier one risk based capital required to be well capitalized to risk weighted assets	8.00%	8.00%
CommonEquityTierOneCapitalAbstract [Abstract]
Common equity tier 1 capital	$ 346,867	$ 348,992
Common equity tier one capital ratio	11.20%	11.90%
Common equity tier one capital required for capital adequacy	$ 139,860	$ 132,065
Common equity tier one capital required for capital adequacy to risk weighted assets	4.50%	4.50%
Common equity tier one capital required to be well-capitalized	$ 202,020	$ 190,760
Common equity tier one capital required to be well capitalized to risk weighted assets	6.50%	6.50%
Tier One Leverage Capital [Abstract]
Tier one leverage capital	$ 346,867	$ 348,992
Tier one leverage capital to average assets	8.80%	9.40%
Tier one leverage capital required for capital adequacy	$ 158,027	$ 148,472
Tier one leverage capital required for capital adequacy to average assets	4.00%	4.00%
Tier one leverage capital required to be well capitalized	$ 197,534	$ 185,590
Tier one leverage capital required to be well capitalized to average assets	5.00%	5.00%
The Columbia Bank
Total Capital [Abstract]
Capital	$ 234,647	$ 203,890
Capital to risk weighted assets	12.20%	12.20%
Capital required for capital adequacy	$ 153,441	$ 133,836
Capital required for capital adequacy to risk weighted assets	8.00%	8.00%
Capital required to be well capitalized	$ 191,801	$ 167,294
Capital required to be well capitalized to risk weighted assets	10.00%	10.00%
Tier One Risk Based Capital [Abstract]
Tier one risk based capital	$ 215,651	$ 185,983
Tier one risk based capital to risk weighted assets	11.20%	11.10%
Tier one risk based capital required for capital adequacy	$ 115,081	$ 100,377
Tier one risk based capital required for capital adequacy to risk weighted assets	6.00%	6.00%
Tier one risk based capital required to be well capitalized	$ 153,441	$ 133,836
Tier one risk based capital required to be well capitalized to risk weighted assets	8.00%	8.00%
CommonEquityTierOneCapitalAbstract [Abstract]
Common equity tier 1 capital	$ 215,651	$ 185,983
Common equity tier one capital ratio	11.20%	11.10%
Common equity tier one capital required for capital adequacy	$ 86,310	$ 72,282
Common equity tier one capital required for capital adequacy to risk weighted assets	4.50%	4.50%
Common equity tier one capital required to be well-capitalized	$ 124,671	$ 108,741
Common equity tier one capital required to be well capitalized to risk weighted assets	6.50%	6.50%
Tier One Leverage Capital [Abstract]
Tier one leverage capital	$ 215,651	$ 185,983
Tier one leverage capital to average assets	9.30%	8.60%
Tier one leverage capital required for capital adequacy	$ 92,797	$ 86,310
Tier one leverage capital required for capital adequacy to average assets	4.00%	4.00%
Tier one leverage capital required to be well capitalized	$ 115,996	$ 107,888
Tier one leverage capital required to be well capitalized to average assets	5.00%	5.00%
Lafayette Ambassador Bank
Total Capital [Abstract]
Capital	$ 173,097	$ 175,254
Capital to risk weighted assets	14.60%	14.60%
Capital required for capital adequacy	$ 94,720	$ 96,100
Capital required for capital adequacy to risk weighted assets	8.00%	8.00%
Capital required to be well capitalized	$ 118,400	$ 120,125
Capital required to be well capitalized to risk weighted assets	10.00%	10.00%
Tier One Risk Based Capital [Abstract]
Tier one risk based capital	$ 162,292	$ 166,186
Tier one risk based capital to risk weighted assets	13.70%	13.80%
Tier one risk based capital required for capital adequacy	$ 71,040	$ 72,075
Tier one risk based capital required for capital adequacy to risk weighted assets	6.00%	6.00%
Tier one risk based capital required to be well capitalized	$ 94,720	$ 96,100
Tier one risk based capital required to be well capitalized to risk weighted assets	8.00%	8.00%
CommonEquityTierOneCapitalAbstract [Abstract]
Common equity tier 1 capital	$ 162,292	$ 166,186
Common equity tier one capital ratio	13.70%	13.80%
Common equity tier one capital required for capital adequacy	$ 53,280	$ 54,056
Common equity tier one capital required for capital adequacy to risk weighted assets	4.50%	4.50%
Common equity tier one capital required to be well-capitalized	$ 76,960	$ 78,081
Common equity tier one capital required to be well capitalized to risk weighted assets	6.50%	6.50%
Tier One Leverage Capital [Abstract]
Tier one leverage capital	$ 162,292	$ 166,186
Tier one leverage capital to average assets	10.10%	10.90%
Tier one leverage capital required for capital adequacy	$ 64,191	$ 61,129
Tier one leverage capital required for capital adequacy to average assets	4.00%	4.00%
Tier one leverage capital required to be well capitalized	$ 80,239	$ 76,412
Tier one leverage capital required to be well capitalized to average assets	5.00%	5.00%