XML 40 R29.htm IDEA: XBRL DOCUMENT v3.20.2
Investment Securities (Tables)
 9 Months Ended
Sep. 30, 2020
Investments, Debt and Equity Securities [Abstract]  
Schedule of amortized cost and estimated fair value of securities
The amortized cost and estimated fair value of securities were as follows:
 September 30, 2020
 Amortized
 Cost		Gross Unrealized
Gain		Gross Unrealized
Loss		Estimated
Fair Value
 (Dollars in thousands)
Investment securities available-for-sale:    
U.S. Treasury$30,161 $2,578 $— $32,739 
Agency577,627 26,109 (691)603,045 
Corporate397,670 2,035 (2,169)397,536 
Municipal bonds1,305,389 23,581 (15,062)1,313,908 
Collateralized mortgage obligations357,615 1,130 (465)358,280 
Mortgage-backed securities868,298 27,121 (196)895,223 
Total investment securities available-for-sale3,536,760 82,554 (18,583)3,600,731 
Investment securities held-to-maturity:
Mortgage-backed securities26,357 1,419 — 27,776 
Other1,623 — — 1,623 
Total investment securities held-to-maturity27,980 1,419 — 29,399 
Total investment securities$3,564,740 $83,973 $(18,583)$3,630,130 
 December 31, 2019
 Amortized
Cost		Gross Unrealized
Gain		Gross Unrealized
Loss		Estimated
Fair Value
 (Dollars in thousands)
Investment securities available-for-sale:    
U.S. Treasury$60,457 $3,137 $(39)$63,555 
Agency240,348 7,686 (1,676)246,358 
Corporate149,150 2,217 (14)151,353 
Municipal bonds384,032 13,450 (184)397,298 
Collateralized mortgage obligations9,869 123 (8)9,984 
Mortgage-backed securities494,404 7,603 (2,171)499,836 
Total investment securities available-for-sale1,338,260 34,216 (4,092)1,368,384 
Investment securities held-to-maturity:
Mortgage-backed securities36,114 922 — 37,036 
Other1,724 — — 1,724 
Total investment securities held-to-maturity37,838 922 — 38,760 
Total investment securities$1,376,098 $35,138 $(4,092)$1,407,144 
Schedule of number, fair value and gross unrealized holding losses of the Company's investment securities by investment category and length of time that the securities have been in a continuous loss position
The table below shows the number, fair value, and gross unrealized holding losses of the Company’s investment securities by investment category and length of time that the securities have been in a continuous loss position.
 September 30, 2020
 Less than 12 Months12 Months or LongerTotal
NumberFair
Value		Gross
Unrealized
Losses		NumberFair
Value		Gross
Unrealized
Losses		NumberFair
Value		Gross
Unrealized
Losses
 (Dollars in thousands)
Investment securities available-for-sale:
U.S. Treasury— $— $— — $— $— — $— $— 
Agency3 57,720 (370)9 11,179 (321)12 68,899 (691)
Corporate17 145,419 (2,169)— — — 17 145,419 (2,169)
Municipal bonds141 776,203 (15,062)— — — 141 776,203 (15,062)
Collateralized mortgage obligations11 129,496 (463)1 476 (2)12 129,972 (465)
Mortgage-backed securities.8 98,253 (196)— — — 8 98,253 (196)
Total investment securities available-for-sale180 $1,207,091 $(18,260)10 $11,655 $(323)190 $1,218,746 $(18,583)

 December 31, 2019
 Less than 12 Months12 Months or LongerTotal
NumberFair
Value		Gross
Unrealized
Losses		NumberFair
Value		Gross
Unrealized
Losses		NumberFair
Value		Gross
Unrealized
Losses
 (Dollars in thousands)
Investment securities available-for-sale:
U.S. Treasury1 $10,194 $(39)— $— $— 1 $10,194 $(39)
Agency13 102,874 (1,340)9 13,514 (336)22 116,388 (1,676)
Corporate1 1,017 (14)— — — 1 1,017 (14)
Municipal bonds12 30,541 (184)— — — 12 30,541 (184)
Collateralized mortgage obligations— — — 1 603 (8)1 603 (8)
Mortgage-backed securities18 130,014 (1,681)11 26,886 (490)29 156,900 (2,171)
Total investment securities available-for-sale45 $274,640 $(3,258)21 $41,003 $(834)66 $315,643 $(4,092)
Schedule of amortized cost and estimated fair value of investment securities available for sale by contractual maturity
The amortized cost and estimated fair value of investment securities at September 30, 2020, by contractual maturity are shown in the table below.
Due in One Year
or Less		Due after One Year
through Five Years		Due after Five Years
through Ten Years		Due after
Ten Years		Total
Amortized
Cost		Fair
Value		Amortized
Cost		Fair
Value		Amortized
Cost		Fair
Value		Amortized
Cost		Fair
Value		Amortized
Cost		Fair
Value
 (Dollars in thousands)
Investment securities available-for-sale:          
U.S. Treasury$— $— $30,161 $32,739 $— $— $— $— $30,161 $32,739 
Agency1,000 1,006 266,255 272,144 234,070 247,806 76,302 82,089 577,627 603,045 
Corporate159,949 160,420 26,391 26,363 156,824 156,934 54,506 53,819 397,670 397,536 
Municipal bonds9,921 10,263 1,458 1,586 36,895 39,849 1,257,115 1,262,210 1,305,389 1,313,908 
Collateralized mortgage obligations— — 3,620 3,622 135,863 136,445 218,132 218,213 357,615 358,280 
Mortgage-backed securities— — 2,190 2,335 197,517 212,743 668,591 680,145 868,298 895,223 
Total investment securities available-for-sale170,870 171,689 330,075 338,789 761,169 793,777 2,274,646 2,296,476 3,536,760 3,600,731 
Investment securities held-to-maturity:
Mortgage-backed securities— — — — — — 26,357 27,776 26,357 27,776 
Other— — — — — — 1,623 1,623 1,623 1,623 
Total investment securities held-to-maturity— — — — — — 27,980 29,399 27,980 29,399 
Total investment securities$170,870 $171,689 $330,075 $338,789 $761,169 $793,777 $2,302,626 $2,325,875 $3,564,740 $3,630,130 
Schedule of Investment Securities by External Credit Rating
The following table summarizes the Company’s investment securities portfolio by Moody’s external rating equivalent and by vintage as of September 30, 2020:
Vintage
20202019201820172016PriorTotal
(Dollars in thousands)
Investment securities available-for-sale:
U.S. Treasury
Aaa - Aa3$— $— $22,006 $10,733 $— $— $32,739 
Agency
Aaa - Aa3284,262 44,884 159,319 9,869 21,246 83,465 603,045 
Corporate debt
A1 - A359,797 19,922 — — 119,221 9,256 208,196 
Baa1 - Baa380,417 41,866 5,074 18,029 8,801 35,153 189,340 
Municipal bonds
Aaa - Aa3904,523 284,555 32,497 50,942 15,238 25,296 1,313,051 
A1 - A3— — — — — 857 857 
Collateralized mortgage obligations
Aaa - Aa3119,689 86,130 14,500 3,975 114,460 19,526 358,280 
Mortgage-backed securities
Aaa - Aa3305,534 182,206 43,802 187,996 85,510 90,175 895,223 
Total investment securities available-for-sale1,754,222 659,563 277,198 281,544 364,476 263,728 3,600,731 
Investment securities held-to-maturity:
Mortgage-backed securities
Aaa - Aa3— — 7,291 6,908 4,613 7,545 26,357 
Other
Baa1 - Baa3— — 628 — — 995 1,623 
Total investment securities held-to-maturity— — 7,919 6,908 4,613 8,540 27,980 
Total investment securities$1,754,222 $659,563 $285,117 $288,452 $369,089 $272,268 $3,628,711