Business Combinations - Rollforward of Acquired Non-Covered Loans With Deterioration of Credit Quality (Detail) (USD $) In Thousands, unless otherwise specified					6 Months Ended	12 Months Ended		6 Months Ended	12 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2014 Non-Covered Loans [Member]	Dec. 31, 2013 Non-Covered Loans [Member]	Jun. 30, 2014 Non-Covered Loans [Member]	Jun. 30, 2014 Loans with Deterioration of Credit Quality [Member] Non-Covered Loans [Member]	Dec. 31, 2013 Loans with Deterioration of Credit Quality [Member] Non-Covered Loans [Member]
Purchased Non Covered Loans [Line Items]
Balance, beginning of year					$ 26,189		$ 32,321	$ 67,165
Charge-offs, net of recoveries								(2,218)
Additions due to acquisitions					7,799	26,189		29,280	67,165
Other (loan payments, transfers, etc.)								(970)
Balance, end of year	$ 49,180	$ 65,441	$ 105,513	$ 159,724				$ 93,257	$ 67,165