Loans and Leases - Summary of Changes in Accretable Yield for Acquired Loans (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Purchased Impaired [Member]
Summary of changes in Accretable Yield for acquired loans
Balance at beginning of period	$ 147,210
Interest income	(49,017)
Reclassifications from nonaccretable balance	36,718
Balance at end of period	134,911
Other Acquired [Member]
Summary of changes in Accretable Yield for acquired loans
Balance at beginning of period	96,907
Interest income	(36,452)
Reclassifications from nonaccretable balance	15,534
Other	(3,909)
Balance at end of period	$ 72,080