Investment Securities (Tables)
 3 Months Ended
Mar. 31, 2016
Investments, Debt and Equity Securities [Abstract]  
Schedule of investment securities available-for-sale
The following table shows investment securities available-for-sale.
(Dollars in thousands)
 
Amortized Cost
 
Gross Unrealized Gains
 
Gross Unrealized Losses
 
Fair Value
March 31, 2016
 
 

 
 

 
 

 
 

U.S. Treasury and Federal agencies securities
 
$
391,488

 
$
2,624

 
$
(42
)
 
$
394,070

U.S. States and political subdivisions securities
 
121,464

 
2,968

 
(123
)
 
124,309

Mortgage-backed securities — Federal agencies
 
237,234

 
4,153

 
(464
)
 
240,923

Corporate debt securities
 
34,183

 
393

 
(1
)
 
34,575

Foreign government and other securities
 
800

 
9

 
—

 
809

Total debt securities
 
785,169

 
10,147

 
(630
)
 
794,686

Marketable equity securities
 
1,893

 
5,670

 
(299
)
 
7,264

Total investment securities available-for-sale
 
$
787,062

 
$
15,817

 
$
(929
)
 
$
801,950

 
 
 
 
 
 
 
 
 
December 31, 2015
 
 

 
 

 
 

 
 

U.S. Treasury and Federal agencies securities
 
$
389,457

 
$
1,718

 
$
(1,506
)
 
$
389,669

U.S. States and political subdivisions securities
 
120,441

 
2,692

 
(143
)
 
122,990

Mortgage-backed securities — Federal agencies
 
234,400

 
3,430

 
(1,533
)
 
236,297

Corporate debt securities
 
34,241

 
199

 
(57
)
 
34,383

Foreign government and other securities
 
800

 
10

 
(1
)
 
809

Total debt securities
 
779,339

 
8,049

 
(3,240
)
 
784,148

Marketable equity securities
 
1,893

 
5,906

 
(220
)
 
7,579

Total investment securities available-for-sale
 
$
781,232

 
$
13,955

 
$
(3,460
)
 
$
791,727
Schedule of contractual maturities of investments in debt securities available-for-sale
The following table shows the contractual maturities of investments in debt securities available-for-sale at March 31, 2016. Expected maturities will differ from contractual maturities, because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.
(Dollars in thousands)
 
Amortized Cost
 
Fair Value
Due in one year or less
 
$
144,949

 
$
145,669

Due after one year through five years
 
384,483

 
389,225

Due after five years through ten years
 
18,503

 
18,869

Due after ten years
 
—

 
—

Mortgage-backed securities
 
237,234

 
240,923

Total debt securities available-for-sale
 
$
785,169

 
$
794,686
Schedule of gross realized gains and losses on sale of securities from securities available-for-sale portfolio
The following table shows the gross realized gains and losses on sale of securities from the securities available-for-sale portfolio, including marketable equity securities. Realized gains and losses on the sales of all securities are computed using the specific identification cost basis.
 
 
Three Months Ended 
 March 31,
(Dollars in thousands)
 
2016
 
2015
Gross realized gains
 
$
10

 
$
—

Gross realized losses
 
—

 
—

Net realized gains (losses)
 
$
10

 
$
—
Schedule of gross unrealized losses and fair value by investment category and age
The following table summarizes gross unrealized losses and fair value by investment category and age.
 
 
Less than 12 Months
 
12 months or Longer
 
Total
(Dollars in thousands) 
 
Fair Value
 
Unrealized Losses
 
Fair Value
 
Unrealized Losses
 
Fair Value
 
Unrealized Losses
March 31, 2016
 
 

 
 

 
 

 
 

 
 

 
 

U.S. Treasury and Federal agencies securities
 
$
36,933

 
$
(42
)
 
$
—

 
$
—

 
$
36,933

 
$
(42
)
U.S. States and political subdivisions securities
 
12,169

 
(73
)
 
4,332

 
(50
)
 
16,501

 
(123
)
Mortgage-backed securities - Federal agencies
 
27,283

 
(111
)
 
19,467

 
(353
)
 
46,750

 
(464
)
Corporate debt securities
 
1,753

 
(1
)
 
—

 
—

 
1,753

 
(1
)
Foreign government and other securities
 
100

 
—

 
—

 
—

 
100

 
—

Total debt securities
 
78,238

 
(227
)
 
23,799

 
(403
)
 
102,037

 
(630
)
Marketable equity securities
 
347

 
(297
)
 
3

 
(2
)
 
350

 
(299
)
Total investment securities available-for-sale
 
$
78,585

 
$
(524
)
 
$
23,802

 
$
(405
)
 
$
102,387

 
$
(929
)
 
 
 
 
 
 
 
 
 
 
 
 
 
December 31, 2015
 
 

 
 

 
 

 
 

 
 

 
 

U.S. Treasury and Federal agencies securities
 
$
151,581

 
$
(928
)
 
$
43,372

 
$
(578
)
 
$
194,953

 
$
(1,506
)
U.S. States and political subdivisions securities
 
17,040

 
(79
)
 
3,795

 
(64
)
 
20,835

 
(143
)
Mortgage-backed securities - Federal agencies
 
78,731

 
(777
)
 
20,592

 
(756
)
 
99,323

 
(1,533
)
Corporate debt securities
 
9,340

 
(57
)
 
—

 
—

 
9,340

 
(57
)
Foreign government and other securities
 
99

 
(1
)
 
—

 
—

 
99

 
(1
)
Total debt securities
 
256,791

 
(1,842
)
 
67,759

 
(1,398
)
 
324,550

 
(3,240
)
Marketable equity securities
 
427

 
(218
)
 
3

 
(2
)
 
430

 
(220
)
Total investment securities available-for-sale
 
$
257,218

 
$
(2,060
)
 
$
67,762

 
$
(1,400
)
 
$
324,980

 
$
(3,460
)