Business Combinations - Additional Information (Detail) $ in Thousands			6 Months Ended
	Jan. 31, 2019 USD ($)	Jan. 31, 2018 USD ($)	Jun. 30, 2019 Property
Sun Bancorp, Inc.
Business Acquisition [Line Items]
Purchase accounting adjustments, assets		$ 2,044,054
Purchase accounting adjustments, loans		1,517,345
Purchase accounting adjustments, deposits		(1,616,073)
Total consideration paid		474,930
Cash consideration		72,400
Core deposit intangible		$ 11,897
Capital Bank
Business Acquisition [Line Items]
Purchase accounting adjustments, assets	$ 494,689
Purchase accounting adjustments, loans	307,703
Purchase accounting adjustments, deposits	(449,018)
Total consideration paid	76,834
Cash consideration	353
Core deposit intangible	$ 2,662
Core Deposits
Business Acquisition [Line Items]
Acquired finite-lived intangible assets, weighted average useful life			10 years
Sun Bancorp, Inc.
Business Acquisition [Line Items]
Number of properties subject to lease agreement | Property			21
Capital Bank
Business Acquisition [Line Items]
Number of properties subject to lease agreement | Property			1