Assets measured at fair value on nonrecurring basis (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014 Fair Value, Inputs, Level 1 [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 1 [Member]	Mar. 31, 2014 Fair Value, Inputs, Level 2 [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 2 [Member]	Mar. 31, 2014 Fair Value, Inputs, Level 3 [Member]	Dec. 31, 2013 Fair Value, Inputs, Level 3 [Member]	Mar. 31, 2014 Fair Value, Measurements, Nonrecurring [Member]		Mar. 31, 2013 Fair Value, Measurements, Nonrecurring [Member]		Mar. 31, 2014 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]		Mar. 31, 2013 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 1 [Member]		Mar. 31, 2014 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]		Mar. 31, 2013 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]		Mar. 31, 2014 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]		Mar. 31, 2013 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 3 [Member]		Mar. 31, 2014 Fair Value, Measurements, Nonrecurring [Member] Unrealized Gain (Loss or Write-down) [Member]		Mar. 31, 2013 Fair Value, Measurements, Nonrecurring [Member] Unrealized Gain (Loss or Write-down) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans							$ 66,189	[1]	$ 16,740	[1]	$ 0	[1]	$ 0	[1]	$ 0	[1]	$ 0	[1]	$ 66,189	[1]	$ 16,740	[1]	$ (11,680)	[1]	$ (10,675)	[1]
Loans held-for-sale	0	0	2,149	3,155	94,201	109,405	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	0	[2]	(2,176)	[2]	(2,176)	[2]
Other real estate owned							17,295	[3]	34,402	[3]	0	[3]	0	[3]	0	[3]	15,645	[3]	17,295	[3]	18,757	[3]	(5,598)	[3]	(15,665)	[3]
Other Repossessed Assets							533	[3]	113	[3]	0	[3]	0	[3]	0	[3]	0	[3]	533	[3]	113	[3]	(271)	[3]	(56)	[3]
Total							$ 84,017		$ 51,255		$ 0		$ 0		$ 0		$ 15,645		$ 84,017		$ 35,610		$ (19,725)		$ (28,572)

[1] Relates mostly to certain impaired collateral dependent loans. The impairment was measured based on the fair value of the collateral, which is derived from appraisals that take into consideration prices in observed transactions involving similar assets in similar locations, in accordance with the provisions of ASC Section 310-10-35. Costs to sell are excluded from the reported fair value amount.

[2] Relates to lower of cost or fair value adjustments on loans held-for-sale and loans transferred from loans held-in-portfolio to loans held-for-sale. Costs to sell are excluded from the reported fair value amount.

[3] Represents the fair value of foreclosed real estate and other collateral owned that were written down to their fair value. Costs to sell are excluded from the reported fair value amount.