Other Borrowings - Summary of Other Borrowings (Parenthetical) (Detail)	6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Daily Rate Credit From Federal Home Loan Bank [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Debt instrument effective rate	0.36%	0.36%	0.36%
Revolving Credit Facility 1 [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% (3.78% at June 30, 2015 and 3.73% at December 31, 2014)
Interest rate, margin to be added	3.50%		3.50%
Debt instrument effective rate	3.78%		3.73%
Debt instrument, maturity period	2016-08		2016-08
Revolving Credit Facility [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Interest rate description	90-day LIBOR plus 4.00% (4.23% at June 30, 2014)
Interest rate, margin to be added		4.00%
Debt instrument effective rate		4.23%
Debt instrument, maturity period	2016-08	2016-08
Correspondent Bank Advances [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Debt instrument effective rate	4.50%	4.50%	4.50%
Maturity period of advances	Nov. 27, 2017	Nov. 27, 2017	Nov. 27, 2017
Subordinated Debt One [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Interest rate description	90-day LIBOR plus 1.60% (1.84% at June 30, 2014)
Interest rate, margin to be added		1.60%
Debt instrument effective rate		1.84%
Debt instrument, maturity period		2016-06
Subordinated Debt Two [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Interest rate description	90-day LIBOR plus 1.75% (2.04% at June 30, 2015, 1.99% at December 31, 2014 and 1.98% at June 30, 2014)
Interest rate, margin to be added	1.75%	1.75%	1.75%
Debt instrument effective rate	2.04%	1.98%	1.99%
Debt instrument, maturity period	2016-09	2016-09	2016-09
Federal Home Loan Bank Advances [Member] | Fixed Rate Advance One [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Debt instrument effective rate	0.20%	0.20%
Maturity period of advances	Jul. 02, 2014	Jul. 02, 2014
Federal Home Loan Bank Advances [Member] | Fixed Rate Advance Two [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Debt instrument effective rate	0.21%	0.21%
Maturity period of advances	Jul. 16, 2014	Jul. 16, 2014
Federal Home Loan Bank Advances [Member] | Fixed Rate Advance Three [Member]
Federal Home Loan Bank Borrowings By Year Of Maturity And Applicable Interest Rate [Line Items]
Debt instrument effective rate	0.19%	0.19%
Maturity period of advances	Jul. 23, 2014	Jul. 23, 2014