Covered Loans - Schedule of Accretable Yield, or Income Expected to be Collected (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Covered Loans [Line Items]
Beginning balance	$ 31,579
New loans purchased
Accretion of income	(11,909)
Reclassifications from (to) nonaccretable difference	(12,338)
Disposals/other adjustments	(367)
Ending balance	31,641
Covered Loans [Member]
Covered Loans [Line Items]
Beginning balance	85,779	92,053
New loans purchased
Accretion of income	(28,103)	(37,919)
Reclassifications from (to) nonaccretable difference	16,689	35,678
Disposals/other adjustments	1,193	411
Ending balance	$ 75,558	$ 90,223