Condensed Parent Company Information - Condensed Balance Sheets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assets:
Securities available for sale	$ 2,093,404	$ 1,660,165
Total assets	22,839,459	20,747,266
Liabilities and Stockholders' Equity:
Long term debt	495,999	374,371
Other liabilities	151,152	171,885
Stockholders' equity	2,413,143	2,472,402	$ 2,425,069	$ 2,453,278
Total liabilities and stockholders' equity	22,839,459	20,747,266
Hancock [Member]
Assets:
Cash	36,364	44,771
Securities available for sale	83,835	97,423
Investment in bank subsidiaries	2,534,299	2,452,529
Investment in non-bank subsidiaries	3,051	3,202
Due from subsidiaries and other assets	31,168	24,896
Total assets	2,688,717	2,622,821
Liabilities and Stockholders' Equity:
Long term debt	275,000	149,600
Other liabilities	574	819
Stockholders' equity	2,413,143	2,472,402
Total liabilities and stockholders' equity	$ 2,688,717	$ 2,622,821