Business Combinations- Summary of Estimated Fair Values of Assets Acquired and Liabilities (Details) - USD ($) $ in Thousands	Jan. 01, 2020	Jan. 31, 2019	Jan. 31, 2018	Dec. 31, 2020	Dec. 31, 2019
Assets acquired:
Bank owned life insurance				$ 265,253	$ 237,411
Liabilities assumed:
Goodwill recorded in the merger				$ 500,319	$ 374,632
Two River Bancorp Acquisition
Business Acquisition [Line Items]
Total Purchase Price:	$ 197,050
Assets acquired:
Cash and cash equivalents	51,102
Securities	64,381
Loans	940,072
Accrued interest receivable	2,382
Bank owned life insurance	22,440
Deferred tax assets, net	3,158
Other assets	15,956
Core deposit intangible	12,130
Total assets acquired	1,111,621
Liabilities assumed:
Deposits	(941,750)
Other liabilities	(59,026)
Total liabilities assumed	(1,000,776)
Net assets acquired	110,845
Goodwill recorded in the merger	86,205
Country Bank Holding Company, Inc. Acquisition
Business Acquisition [Line Items]
Total Purchase Price:	112,836
Assets acquired:
Cash and cash equivalents	20,799
Securities	144,499
Loans	618,408
Accrued interest receivable	1,779
Deferred tax assets, net	(3,117)
Other assets	9,195
Core deposit intangible	2,117
Total assets acquired	793,680
Liabilities assumed:
Deposits	(652,653)
Other liabilities	(67,240)
Total liabilities assumed	(719,893)
Net assets acquired	73,787
Goodwill recorded in the merger	$ 39,049
Capital Bank
Business Acquisition [Line Items]
Total Purchase Price:		$ 76,834
Assets acquired:
Cash and cash equivalents		59,748
Securities		103,775
Loans		307,300
Accrued interest receivable		1,390
Bank owned life insurance		10,460
Deferred tax assets, net		4,101
Other assets		4,980
Core deposit intangible			$ 11,897
Total assets acquired		494,416
Liabilities assumed:
Deposits		(449,018)
Other liabilities		(5,210)
Total liabilities assumed		(454,228)
Net assets acquired		40,188
Goodwill recorded in the merger		36,646
Sun Bancorp, Inc.
Business Acquisition [Line Items]
Total Purchase Price:			474,930
Assets acquired:
Cash and cash equivalents			68,632
Securities			254,522
Loans			1,517,345
Accrued interest receivable			5,621
Bank owned life insurance			85,238
Deferred tax assets, net			57,597
Other assets			43,202
Core deposit intangible		$ 2,662
Total assets acquired			2,044,054
Liabilities assumed:
Deposits			(1,616,073)
Borrowings			(127,727)
Other liabilities			(13,242)
Total liabilities assumed			(1,757,042)
Net assets acquired			287,012
Goodwill recorded in the merger			$ 187,918