Other Borrowings - Summary of Other Borrowings (Parenthetical) (Detail)		9 Months Ended	12 Months Ended		9 Months Ended			9 Months Ended		9 Months Ended	12 Months Ended
	Sep. 30, 2014 Federal Home Loan Bank Advances [Member]	Sep. 30, 2014 Revolving Credit Facility 1 [Member]	Dec. 31, 2013 Revolving Credit Facility [Member]	Sep. 30, 2013 Revolving Credit Facility [Member]	Sep. 30, 2014 Correspondent Bank Advances [Member]	Sep. 30, 2014 Subordinated Debt One [Member]	Dec. 31, 2013 Subordinated Debt One [Member]	Sep. 30, 2014 Subordinated Debt Two [Member]	Dec. 31, 2013 Subordinated Debt Two [Member]	Sep. 30, 2014 Fixed Rate Advance One [Member] Federal Home Loan Bank Advances [Member]	Dec. 31, 2013 Fixed Rate Advance Two [Member] Federal Home Loan Bank Advances [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Interest rate description		90-day LIBOR plus 3.50% (3.73% at September 30, 2014)	90-day LIBOR plus 4.00% (4.24% and 4.27% at December 31, 2013 and September 30, 2013)			90-day LIBOR plus 1.60% (1.83% and 1.84% at September 30, 2014 and December 31, 2013)		90-day LIBOR plus 1.75% (1.98% and 1.99% at September 30, 2014 and December 31, 2013)
Federal Home Loan Bank Advances effective rate	0.36%									0.16%	0.17%
Interest rate, margin to be added		3.50%	4.00%			1.60%		1.75%
90-day LIBOR interest rate at period end		3.73%	4.24%	4.27%	4.50%	1.83%	1.84%	1.98%	1.99%
Maturity period of Federal Home Loan Bank advances		2016-08	2016-08			2016-06		2016-09
Maturity period of advances					Nov. 27, 2017					Oct. 24, 2014	Jan. 24, 2014