Carrying Amounts and Estimated Fair Values of Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Financial assets
Cash and cash equivalents	$ 333,639	$ 110,118
Time deposits in financial institutions	1,745	1,846
Securities available-for-sale	107,525	170,022
FHLB and other bank stock	26,801	22,600
Loans held for sale	1,000,394	719,496
Loans and leases receivable, net of allowance	2,414,917	2,460,953
Accrued interest receivable	10,962	10,866
Derivative assets	4,469	5,493
Financial liabilities
Deposits	3,074,457	2,877,650
Advances from the FHLB	395,074	250,090
Federal funds purchased	70,000
Notes payable	86,615	85,564
Derivative liabilities	64
Accrued interest payable	1,628	1,646
Level 1
Financial assets
Cash and cash equivalents	333,639	110,118
Time deposits in financial institutions	1,745	1,846
Accrued interest receivable	10,962	10,866
Financial liabilities
Federal funds purchased	70,000
Notes payable	86,615	85,564
Accrued interest payable	1,628	1,646
Level 2
Financial assets
Securities available-for-sale	107,525	170,022
FHLB and other bank stock	26,801	22,600
Loans held for sale	1,000,394	719,496
Derivative assets	4,469	5,493
Financial liabilities
Deposits	3,074,457	2,877,650
Advances from the FHLB	395,074	250,090
Derivative liabilities	64
Level 3
Financial assets
Loans and leases receivable, net of allowance	2,414,917	2,460,953
Carrying value
Financial assets
Cash and cash equivalents	333,639	110,118
Time deposits in financial institutions	1,745	1,846
Securities available-for-sale	107,525	170,022
FHLB and other bank stock	26,801	22,600
Loans held for sale	1,000,394	716,733
Loans and leases receivable, net of allowance	2,376,992	2,427,306
Accrued interest receivable	10,962	10,866
Derivative assets	4,469	5,493
Financial liabilities
Deposits	3,109,146	2,918,644
Advances from the FHLB	395,000	250,000
Federal funds purchased	70,000
Notes payable	82,416	82,320
Derivative liabilities	64
Accrued interest payable	$ 1,628	$ 1,646