Other Borrowings - Summary of Other Borrowings (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Other borrowings	$ 194,572
Fixed Rate Advance One [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Advance from Federal Home Loan Bank with a fixed interest rate of 0.17%, due January 24, 2014	165,000
Revolving Credit Facility [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Advances under revolving credit agreement with a regional bank with interest at 90-day LIBOR plus 4.00% (4.24% at December 31, 2013) due in August 2016, secured by subsidiary bank stock	10,000
Subordinated Debt One [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Subordinated debt issued by Prosperity Bank due June 2016 with an interest rate of 90-day LIBOR plus 1.60% (1.84% at December 31, 2013)	5,000
Subordinated Debt Two [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Subordinated debt issued by Prosperity Bank due June 2016 with an interest rate of 90-day LIBOR plus 1.60% (1.84% at December 31, 2013)	$ 14,572