XML 142 R63.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Investment Securities - Summary of Interest Income Earned on Investment Securities (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Net Investment Income [Line Items]      
Total interest income from available-for-sale securities $ 39,330 $ 45,988 $ 49,778
Total interest income from held-to-maturity securities 17,388 18,901 21,015
Total investment income 56,718 64,889 70,793
Investment securities available-for-sale [Member]      
Net Investment Income [Line Items]      
Taxable 38,189 44,423 47,596
Tax-advantaged 1,141 1,565 2,182
Total interest income from available-for-sale securities 39,330 45,988 49,778
Investment securities held-to-maturity [Member]      
Net Investment Income [Line Items]      
Taxable 11,498 11,848 12,558
Tax-advantaged 5,890 7,053 8,457
Total interest income from held-to-maturity securities $ 17,388 $ 18,901 $ 21,015