Allowance for Loan Losses - Change in Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Changes in the allowance for loan losses
Balance at the beginning of period	$ 37,066	$ 35,569
Provision charged to operations	4,400	4,600
Loans charged off	(5,898)	(5,762)
Recoveries of loans previously charged off	1,166	1,431
Balance at the end of period	36,734	35,838
Real estate - residential mortgage
Changes in the allowance for loan losses
Balance at the beginning of period	2,559	2,471
Provision charged to operations	(33)	(10)
Loans charged off	(5)
Recoveries of loans previously charged off	14	26
Balance at the end of period	2,535	2,487
Real estate - construction
Changes in the allowance for loan losses
Balance at the beginning of period	816	94
Provision charged to operations	(75)	192
Balance at the end of period	741	286
Commercial, financial and agricultural
Changes in the allowance for loan losses
Balance at the beginning of period	7,393	7,755
Provision charged to operations	259	(226)
Loans charged off	(153)	(35)
Recoveries of loans previously charged off	7	160
Balance at the end of period	7,506	7,654
Equity lines
Changes in the allowance for loan losses
Balance at the beginning of period	685	1,052
Provision charged to operations	27	91
Loans charged off		(55)
Balance at the end of period	712	1,088
Consumer Loan
Changes in the allowance for loan losses
Balance at the beginning of period	261	243
Provision charged to operations	(78)	(47)
Loans charged off	(62)	(71)
Recoveries of loans previously charged off	41	127
Balance at the end of period	162	252
Consumer Finance
Changes in the allowance for loan losses
Balance at the beginning of period	25,352	23,954
Provision charged to operations	4,300	4,600
Loans charged off	(5,678)	(5,601)
Recoveries of loans previously charged off	1,104	1,118
Balance at the end of period	$ 25,078	$ 24,071