Allowance for Loan Losses on PCI Loans and Recorded Investment in Loans (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Acquired Impaired Loans Evaluated for Impairment	$ 28,429	$ 42,642
Allowance for Acquired Impaired Loans Evaluated	12	54
Commercial Loans
Financing Receivable, Recorded Investment [Line Items]
Acquired Impaired Loans Evaluated for Impairment	5,846	10,567
Commercial Loans | Waccamaw Commercial
Financing Receivable, Recorded Investment [Line Items]
Acquired Impaired Loans Evaluated for Impairment	260	3,788
Commercial Loans | Peoples Commercial
Financing Receivable, Recorded Investment [Line Items]
Acquired Impaired Loans Evaluated for Impairment	4,491	5,525
Commercial Loans | Commercial Loan Other
Financing Receivable, Recorded Investment [Line Items]
Acquired Impaired Loans Evaluated for Impairment	1,095	1,254
Consumer Real Estate
Financing Receivable, Recorded Investment [Line Items]
Acquired Impaired Loans Evaluated for Impairment	22,583	32,075
Allowance for Acquired Impaired Loans Evaluated	12	54
Consumer Real Estate | Waccamaw Serviced Home Equity Lines
Financing Receivable, Recorded Investment [Line Items]
Acquired Impaired Loans Evaluated for Impairment	20,178	29,241
Consumer Real Estate | Waccamaw Residential
Financing Receivable, Recorded Investment [Line Items]
Acquired Impaired Loans Evaluated for Impairment	1,320	1,678
Allowance for Acquired Impaired Loans Evaluated		1
Consumer Real Estate | Peoples Residential
Financing Receivable, Recorded Investment [Line Items]
Acquired Impaired Loans Evaluated for Impairment	1,085	1,156
Allowance for Acquired Impaired Loans Evaluated	$ 12	$ 53