Securities (Details Textual)	12 Months Ended
	Dec. 31, 2016 USD ($) security	Dec. 31, 2016 USD ($) institution	Dec. 31, 2016 USD ($)	Dec. 31, 2016 USD ($) Tranche	Dec. 31, 2015 USD ($) security	Dec. 31, 2014 USD ($) security
Schedule of Available-for-sale Securities [Line Items]
Investments in pooled trust preferred securities, cost basis	$ 686,405,000	$ 686,405,000	$ 686,405,000	$ 686,405,000	$ 1,117,000	$ 724,000
Available-for-sale securities, net proceeds					1,213,000	1,099,000
Available-for-sale securities, gross realized gain (loss)			1,186,000		96,000	$ 375,000
Securities available for sale, at fair value	$ 674,248,000	$ 674,248,000	674,248,000	$ 674,248,000	$ 646,805,000
Number of securities representing interests in tranches of trusts (tranches)	3			3	3
Number of institutions issuing debt (institutions) | institution		250
Number of securities, return to accrual status | security					1	1
Trust preferred securities
Schedule of Available-for-sale Securities [Line Items]
Investments in pooled trust preferred securities, cost basis	$ 23,749,000	$ 23,749,000	23,749,000	$ 23,749,000	$ 24,770,000
Securities available for sale, at fair value	18,389,000	18,389,000	18,389,000	18,389,000	19,469,000
Other than temporary impairment losses			0		0	$ 0
Secure government, public and trust deposits
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities pledged as collateral	642,447,000	642,447,000	642,447,000	642,447,000	679,492,000
Short-term borrowings
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities pledged as collateral	24,426,000	24,426,000	24,426,000	24,426,000	39,275,000
Heritage Financial Group
Schedule of Available-for-sale Securities [Line Items]
Investments in pooled trust preferred securities, cost basis					7,231,000
Available-for-sale securities, net proceeds					7,231,000
Available-for-sale securities, gross realized gain (loss)					0
Trust preferred securities
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, at fair value	18,389,000	18,389,000	18,389,000	18,389,000	$ 19,469,000
Trust preferred securities | Pooled Trust Preferred Securities Xiii
Schedule of Available-for-sale Securities [Line Items]
Investments in pooled trust preferred securities, cost basis	$ 2,842,000	$ 2,842,000	2,842,000	$ 2,842,000
Available-for-sale securities, net proceeds			4,028,000
Available-for-sale securities, gross realized gain (loss)			$ 1,186,000