Loans and Leases and Other Real Estate - Lakeland's Non-Accrual Loans and Leases and Its Accruing Troubled Debt Restructurings (TDRs) (Detail) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	$ 12,130	$ 13,655
Other real estate and other repossessed assets	830	843
Total non-performing assets	12,960	14,498
Troubled debt restructurings, still accruing	9,293	11,462
Commercial, secured by real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	7,192	5,890
Commercial, industrial and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	1,019	184
Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	501	144
Real estate - residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	1,986	3,860
Real estate - construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	0	1,472
Home equity and consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total non-accrual loans and leases	$ 1,432	$ 2,105