Borrowings - Junior Subordinated Debt Trusts (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 109,987	$ 48,600
Trust Preferred Securities Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	115,500
Common Stock Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	3,885
F.N.B. Statutory Trust II [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 22,165
Stated Maturity Date	Jun. 15, 2036
Interest Rate	2.78%
Description of variable rate	Variable; LIBOR + 165 basis points (bps)
Basis points	1.65%
F.N.B. Statutory Trust II [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 21,500
F.N.B. Statutory Trust II [Member] | Common Stock Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	665
Omega Financial Capital Trust I [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 26,445
Stated Maturity Date	Oct. 18, 2034
Interest Rate	3.21%
Description of variable rate	Variable; LIBOR + 219 bps
Basis points	2.19%
Omega Financial Capital Trust I [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 26,000
Omega Financial Capital Trust I [Member] | Common Stock Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	1,114
Yadkin Valley Statutory Trust I [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 20,677
Stated Maturity Date	Dec. 15, 2037
Interest Rate	2.45%
Description of variable rate	Variable; LIBOR + 132 bps
Basis points	1.32%
Yadkin Valley Statutory Trust I [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 25,000
Yadkin Valley Statutory Trust I [Member] | Common Stock Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	774
FNB Financial Services Capital Trust I [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 21,635
Stated Maturity Date	Sep. 30, 2035
Interest Rate	2.59%
Description of variable rate	Variable; LIBOR + 146 bps
Basis points	1.46%
FNB Financial Services Capital Trust I [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 25,000
FNB Financial Services Capital Trust I [Member] | Common Stock Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	774
American Community Capital Trust II [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 10,455
Stated Maturity Date	Dec. 15, 2033
Interest Rate	3.80%
Description of variable rate	Variable; LIBOR + 280 bps
Basis points	2.80%
American Community Capital Trust II [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 10,000
American Community Capital Trust II [Member] | Common Stock Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	310
Crescent Financial Capital Trust I [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 8,610
Stated Maturity Date	Oct. 07, 2033
Interest Rate	4.12%
Description of variable rate	Variable; LIBOR + 310 bps
Basis points	3.10%
Crescent Financial Capital Trust I [Member] | Trust Preferred Securities Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 8,000
Crescent Financial Capital Trust I [Member] | Common Stock Subject to Mandatory Redemption [Member]
Subordinated Borrowing [Line Items]
Junior subordinated debt	$ 248