Condensed Parent Company Only Financial Statements - Condensed Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash in bank	$ 289,794	$ 294,186
Other assets	1,004,749	1,039,783
Total Assets	31,713,450	30,833,015	$ 27,904,129
Liabilities and Shareholders’ Equity
Liabilities	27,376,716	26,776,738
Shareholders’ equity	4,336,734	4,056,277	$ 3,696,791	$ 2,939,694
Total Liabilities and Shareholders’ Equity	31,713,450	30,833,015
IBERIABANK Corporation
Assets
Cash in bank	160,171	179,545
Investments in subsidiaries	4,308,843	4,008,802
Other assets	63,205	53,832
Total Assets	4,532,219	4,242,179
Liabilities and Shareholders’ Equity
Liabilities	195,485	185,902
Shareholders’ equity	4,336,734	4,056,277
Total Liabilities and Shareholders’ Equity	$ 4,532,219	$ 4,242,179