Loans and Leases - Summary of Acquisition of Purchased Loans (Detail) - USD ($) $ in Thousands		12 Months Ended
	Feb. 13, 2016	Dec. 31, 2016	Dec. 31, 2015
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Contractually required cash flows at acquisition	$ 2,291,087
Non-accretable difference (expected losses and foregone interest)	(317,228)
Cash flows expected to be collected at acquisition	1,973,859
Accretable yield	(308,311)	$ (103,730)	$ (60,171)
Basis in acquired loans at acquisition	1,665,548
Acquired Impaired Loans [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Contractually required cash flows at acquisition	99,611
Non-accretable difference (expected losses and foregone interest)	(52,995)
Cash flows expected to be collected at acquisition	46,616
Accretable yield	(1,063)
Basis in acquired loans at acquisition	45,553
Acquired Performing Loans [Member]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Line Items]
Contractually required cash flows at acquisition	2,191,476
Non-accretable difference (expected losses and foregone interest)	(264,233)
Cash flows expected to be collected at acquisition	1,927,243
Accretable yield	(307,248)
Basis in acquired loans at acquisition	$ 1,619,995