Business Combination - Additional Information (Detail) $ in Thousands		3 Months Ended								12 Months Ended
	Jan. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) Property	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Merger related expenses		$ 1,288	$ 2,030	$ 8,434	$ 18,310	$ 1,259	$ 3,153	$ 8,606	$ 1,480	$ 26,911	$ 8,293	$ 16,534
Ocean Shore Holdings Co.
Business Acquisition [Line Items]
Consideration paid	$ 474,930
Sun Bancorp, Inc.
Business Acquisition [Line Items]
Purchase accounting adjustments, assets	2,044,031
Purchase accounting adjustments, loans	1,517,345
Purchase accounting adjustments, deposits	1,616,073
Consideration paid	474,900
Cash consideration paid for outstanding warrants and fractional shares	72,400
Number of properties in lease agreements | Property										21
Core deposit intangible	$ 11,897