Mergers and Acquisitions - Narrative (Details)					1 Months Ended	3 Months Ended		11 Months Ended	12 Months Ended
	Feb. 01, 2018 USD ($)	Nov. 01, 2017 USD ($) bank_branch $ / shares shares	Jul. 31, 2017 USD ($) shares	Jul. 01, 2016 USD ($) bank_branch $ / shares	Jan. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Goodwill								$ 307,112,000	$ 307,112,000	$ 220,591,000	$ 142,025,000
Goodwill adjustment									(858,000)
NLFC Holdings Corp
Business Acquisition [Line Items]
Assets acquired	$ 393,300,000
Liabilities assumed	350,433,000
Consideration transferred	130,246,000
Cash consideration	84,500,000
Common stock issued as consideration	45,746,000
Goodwill	87,379,000
Goodwill expected to be tax deductible	0
Provisional value adjustment decrease to acquired loans								526,000
Goodwill adjustment								$ 390,000
Value of loans acquired separate from the business combination					$ 19,900,000
Premises and equipment, net	$ 324,000
Merger related costs included in pro forma results									$ 4,980,000
Four Oaks FinCorp, Inc
Business Acquisition [Line Items]
Assets acquired		$ 730,491,000
Liabilities assumed		657,566,000
Consideration transferred		126,467,000
Cash consideration		12,802,000
Common stock issued as consideration		$ 113,665,000
Number of shares received for each share outstanding (in shares) | shares		0.6178
Cash per common share outstanding (in dollars per share) | $ / shares		$ 1.90
Goodwill		$ 53,542,000
Goodwill expected to be tax deductible		$ 0
Goodwill adjustment							$ (1,160,000)
Expected useful life of asset		1 year
Noncompete agreement		$ 908,000
Premises and equipment, net		12,398,000
Loans held for sale		10,686,000					10,700,000
Servicing assets							65,000
Provisional value adjustment increase to loans held for sale							2,590,000
Provisional value adjustment decrease to servicing assets							354,000
Provisional value adjustment for deferred tax asset							$ (1,080,000)
Four Oaks FinCorp, Inc | Trust preferred securities
Business Acquisition [Line Items]
Liabilities assumed		12,400,000
Four Oaks FinCorp, Inc | Subordinated debentures
Business Acquisition [Line Items]
Liabilities assumed		11,500,000
Four Oaks FinCorp, Inc | Core deposit intangible
Business Acquisition [Line Items]
Intangible assets acquired		$ 7,830,000
Expected useful life of asset		11 years 6 months
Four Oaks FinCorp, Inc | Four Oaks Bank
Business Acquisition [Line Items]
Number of branches | bank_branch		14
HCSB Financial Corporation
Business Acquisition [Line Items]
Assets acquired			$ 389,436,000
Liabilities assumed			346,646,000
Consideration transferred			65,831,000
Cash consideration			31,000
Common stock issued as consideration			$ 65,800,000
Number of shares received for each share outstanding (in shares) | shares			0.0050
Goodwill			$ 24,166,000
Goodwill expected to be tax deductible			0
Goodwill adjustment						$ 303,000
Noncompete agreement			2,240,000
Premises and equipment, net			$ 7,424,000
Provisional value adjustment for deferred tax asset						190,000
Provisional value adjustment decrease to premises and equipment						$ 493,000
HCSB Financial Corporation | Minimum
Business Acquisition [Line Items]
Useful life of intangible asset			1 year
HCSB Financial Corporation | Maximum
Business Acquisition [Line Items]
Useful life of intangible asset			2 years
HCSB Financial Corporation | Core deposit intangible
Business Acquisition [Line Items]
Intangible assets acquired			$ 3,480,000
Expected useful life of asset			6 years
Four Oaks Fin Corp, Inc and HCSB Financial Corporation
Business Acquisition [Line Items]
Merger related costs included in pro forma results										$ 8,710,000
Tidelands Bancshares, Inc
Business Acquisition [Line Items]
Assets acquired				$ 440,245,000
Liabilities assumed				439,749,000
Consideration transferred				$ 11,209,000
Cash per common share outstanding (in dollars per share) | $ / shares				$ 0.52
Goodwill				$ 10,713,000
Goodwill expected to be tax deductible				0
Premises and equipment, net				11,189,000
Loans held for sale				142,000
Cash paid to redeem common stock				2,224,000
Cash paid to redeem preferred stock including unpaid dividends				8,985,000
Merger related costs excluded from pro forma results											$ 4,070,000
Tidelands Bancshares, Inc | Core deposit intangible
Business Acquisition [Line Items]
Intangible assets acquired				$ 1,570,000
Expected useful life of asset				5 years
Tidelands Bancshares, Inc | Tidelands Bank
Business Acquisition [Line Items]
Number of branches | bank_branch				7