Non-interest Income and Expense - Components of Non-Interest Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Schedule Of Other Noninterest Income And Expense [Line Items]
Total service charges and fees	$ 8,168	$ 10,128	$ 17,294	$ 19,198
Increase in cash value of life insurance	710	746	1,430	1,521
Asset management and commission income	661	739	1,577	1,381
Gain on sale of loans	1,736	575	2,627	987
Lease brokerage income	127	239	320	459
Sale of customer checks	88	135	212	275
Gain on marketable equity securities	25	42	72	78
Other	142	819	(55)	1,327
Total other non-interest income	3,489	3,295	6,183	6,028
Total non-interest income	11,657	13,423	23,477	25,226
ATM and interchange fees
Schedule Of Other Noninterest Income And Expense [Line Items]
Total service charges and fees	5,165	5,404	10,276	9,985
Service charges on deposit accounts
Schedule Of Other Noninterest Income And Expense [Line Items]
Total service charges and fees	3,046	4,182	7,092	8,062
Other service fees
Schedule Of Other Noninterest Income And Expense [Line Items]
Total service charges and fees	734	619	1,492	1,390
Mortgage banking service fees
Schedule Of Other Noninterest Income And Expense [Line Items]
Total service charges and fees	459	475	928	958
Change in value of mortgage servicing rights
Schedule Of Other Noninterest Income And Expense [Line Items]
Total service charges and fees	$ (1,236)	$ (552)	$ (2,494)	$ (1,197)