AFS Securities (Tables)

9 Months Ended

Sep. 30, 2018

Investments, Debt and Equity Securities [Abstract]

Amortized cost and fair value of available-for-sale securities

The amortized cost and fair value of AFS securities, with gross unrealized gains and losses, are as follows at:



	September 30, 2018
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Government sponsored enterprises	$	184	$	—	$	4	$	180
States and political subdivisions	193,195		1,328		566		193,957
Auction rate money market preferred	3,200		—		92		3,108
Mortgage-backed securities	196,194		21		8,079		188,136
Collateralized mortgage obligations	120,096		17		4,355		115,758
Total	$	512,869	$	1,366	$	13,096	$	501,139



	December 31, 2017
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Government sponsored enterprises	$	217	$	—	$	1	$	216
States and political subdivisions	204,131		4,486		143		208,474
Auction rate money market preferred	3,200		—		151		3,049
Mortgage-backed securities	210,757		390		2,350		208,797
Collateralized mortgage obligations	129,607		160		1,573		128,194
Total	$	547,912	$	5,036	$	4,218	$	548,730

Amortized cost and fair value of available-for-sale securities by contractual maturity

The amortized cost and fair value of AFS securities by contractual maturity at September 30, 2018 are as follows:



	Maturing								Securities with Variable Monthly Payments or Noncontractual Maturities
	Due in One Year or Less		After One Year But Within Five Years		After Five Years But Within Ten Years		After Ten Years				Total
Government sponsored enterprises	$	—	$	184	$	—	$	—	$	—	$	184
States and political subdivisions	22,802		80,091		61,348		28,954		—		193,195
Auction rate money market preferred	—		—		—		—		3,200		3,200
Mortgage-backed securities	—		—		—		—		196,194		196,194
Collateralized mortgage obligations	—		—		—		—		120,096		120,096
Total amortized cost	$	22,802	$	80,275	$	61,348	$	28,954	$	319,490	$	512,869
Fair value	$	22,850	$	80,589	$	61,855	$	28,843	$	307,002	$	501,139

Schedule of Realized Gain (Loss) [Table Text Block]

A summary of the sales activity of AFS securities was as follows for the:



	Three Months Ended September 30				Nine Months Ended September 30
	2018		2017		2018		2017
Proceeds from sales of AFS securities	$	—	$	—	$	—	$	12,827
Gross realized gains (losses)	$	—	$	—	$	—	$	142
Applicable income tax expense (benefit)	$	—	$	—	$	—	$	48

Available-for-sale securities with gross unrealized losses

The following information pertains to AFS securities with gross unrealized losses at September 30, 2018 and December 31, 2017, aggregated by investment category and length of time that individual securities have been in a continuous loss position.



	September 30, 2018
	Less Than Twelve Months				Twelve Months or More
	Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Total Unrealized Losses
Government sponsored enterprises	$	4	$	180	$	—	$	—	$	4
States and political subdivisions	566		41,972		—		—		566
Auction rate money market preferred	—		—		92		3,108		92
Mortgage-backed securities	2,780		89,602		5,299		96,985		8,079
Collateralized mortgage obligations	2,198		72,074		2,157		39,948		4,355
Total	$	5,548	$	203,828	$	7,548	$	140,041	$	13,096
Number of securities in an unrealized loss position:			164				37		201



	December 31, 2017
	Less Than Twelve Months				Twelve Months or More
	Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Total Unrealized Losses
Government sponsored enterprises	$	1	$	216	$	—	$	—	$	1
States and political subdivisions	142		16,139		1		188		143
Auction rate money market preferred	—		—		151		3,049		151
Mortgage-backed securities	454		72,007		1,896		76,065		2,350
Collateralized mortgage obligations	701		76,435		872		25,308		1,573
Total	$	1,298	$	164,797	$	2,920	$	104,610	$	4,218
Number of securities in an unrealized loss position:			81				24		105