Securities - Summary of Structured Pooled Trust Preferred Securities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Adjusted Amortized Cost	$ 800
Unrealized Gain (Loss)	2,613
Fair Value	3,413
Credit Losses Realized in Earnings	0	$ 0	$ 0
ALESCO Preferred Funding V, Ltd [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Amortized Cost	800
Unrealized Gain (Loss)	370
Fair Value	1,170
Credit Losses Realized in Earnings	0	0	0
ALESCO Preferred Funding XII, Ltd [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Amortized Cost	0
Unrealized Gain (Loss)	1,021
Fair Value	1,021
Credit Losses Realized in Earnings	0	0	0
ALESCO Preferred Funding XVII, Ltd [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Amortized Cost	0
Unrealized Gain (Loss)	588
Fair Value	588
Credit Losses Realized in Earnings	0	0	0
Preferred Term Securities XVI, Ltd [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Amortized Cost	0
Unrealized Gain (Loss)	634
Fair Value	634
Credit Losses Realized in Earnings	0	0	0
US Capital Funding VI, Ltd. [Member]
Schedule of Available-for-sale Securities [Line Items]
Adjusted Amortized Cost	0
Unrealized Gain (Loss)	0
Fair Value	0
Credit Losses Realized in Earnings	$ 0	$ 0	$ 0