Long-Term Borrowings (Narrative) (Detail) (USD $)	12 Months Ended		12 Months Ended
	Dec. 31, 2012 Trust	Dec. 31, 2011	Dec. 31, 2012 Long-term Borrowings [Member]	Dec. 31, 2011 Long-term Borrowings [Member]	Dec. 31, 2010 Long-term Borrowings [Member]	Dec. 31, 2012 Centra Financial Holdings Inc [Member] Trust	Jul. 08, 2011 Centra Financial Holdings Inc [Member]
Debt Instrument [Line Items]
Carrying value of loans pledged as collateral for FHLB advances	$ 3,384,767,000
Unused borrowing amount	1,631,370,000
FHLB advances	186,411,000	141,809,000
FHLB overnight funds	100,000,000
Number of statutory business trusts	12					2
Outstanding balances of debentures	198,515,000	203,557,000					20,000,000
Maximum time to defer payment of interest on subordinate debt	5 years
Interest paid			$ 14,370,000	$ 16,335,000	$ 29,990,000