Loans and Allowance for Credit Losses - Schedule of Accretable Yield of Noncovered Loans, or Income Expected to be Collected (Detail) (Non Covered Loans [Member], USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at January 1	$ 28,291
New loans purchased	4,065
Accretion of income	(9,751)
Reclassifications from (to) nonaccretable difference	2,181
Disposals/other adjustments	563
Balance at June 30	25,349
Monroe Bancorp [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at January 1	6,787
Accretion of income	(1,792)
Reclassifications from (to) nonaccretable difference	(1,081)
Disposals/other adjustments	640
Balance at June 30	4,554
Integra Noncovered [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at January 1	2,425
Accretion of income	(481)
Reclassifications from (to) nonaccretable difference	(149)
Disposals/other adjustments	(77)
Balance at June 30	1,718
IBT [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance at January 1	19,079
Accretion of income	(7,252)
Reclassifications from (to) nonaccretable difference	3,411
Balance at June 30	15,238
Tower [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
New loans purchased	4,065
Accretion of income	(226)
Balance at June 30	$ 3,839