Goodwill and Intangible Assets - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010 Minimum [Member] Y	Dec. 31, 2010 Maximum [Member] Y	Dec. 31, 2013 Prosperity Bank [Member]	Dec. 31, 2010 Tifton Banking Company (TBC) [Member]
Goodwill And Core Deposit Intangibles [Line Items]
Core deposit intangible assets	$ 4,383,000	$ 1,149,000	$ 0
Goodwill						34,093,000	956,000
Amortization period of core deposit intangibles				3	10
Aggregate amortization expense for intangible assets	$ 1,414,000	$ 1,359,000	$ 1,011,000