Business Combinations - Additional Information (Detail) $ in Thousands			11 Months Ended	12 Months Ended
	Jan. 31, 2019 USD ($) Property	Jan. 31, 2018 USD ($)	Dec. 31, 2018 Property	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Business Acquisition [Line Items]
Merger related expenses				$ 10,503	$ 26,911	$ 8,293
Capital Bank
Business Acquisition [Line Items]
Purchase accounting adjustments, assets	$ 494,760
Purchase accounting adjustments, loans	307,778
Deposits	(449,018)
Consideration paid	76,834
Cash consideration paid for outstanding warrants and fractional shares	$ 353
Number of properties in lease agreements | Property	1
Core deposit intangible	$ 2,662
Sun Bancorp, Inc.
Business Acquisition [Line Items]
Purchase accounting adjustments, assets		$ 2,044,054
Purchase accounting adjustments, loans		1,517,345
Deposits		(1,616,073)
Consideration paid		474,930
Cash consideration paid for outstanding warrants and fractional shares		72,400
Number of properties in lease agreements | Property			21
Core deposit intangible		$ 11,897
Weighted average useful life (years)				10 years