Securities (Details Textual)	3 Months Ended		12 Months Ended
	Jun. 30, 2015 security	Jun. 30, 2014 security	Dec. 31, 2015 USD ($) security	Dec. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) Tranche	Dec. 31, 2015 USD ($) institution	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Carrying value of securities held to maturity								$ 4,290,000
Net gain recognized on sale of securities held to maturity								169,000
Securities classified as held to maturity				$ 0			$ 0
Investments in pooled trust preferred securities, cost basis			$ 647,658,000	647,658,000	$ 647,658,000	$ 647,658,000	724,000	9,130,000
Available-for-sale securities, net proceeds							1,099,000	9,015,000
Available-for-sale securities, gross realized gain (loss)				96,000			375,000	(115,000)
Fair Value			$ 646,805,000	646,805,000	$ 646,805,000	$ 646,805,000	553,584,000
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			$ 24,770,000	24,770,000	$ 24,770,000	$ 24,770,000	26,400,000
Fair Value			19,469,000	19,469,000	19,469,000	19,469,000	19,756,000
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			679,492,000	679,492,000	679,492,000	679,492,000	617,189,000
Short-term borrowings
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities pledged as collateral			39,275,000	39,275,000	39,275,000	39,275,000	16,410,000
Trust preferred securities
Schedule of Available-for-sale Securities [Line Items]
Fair Value			19,469,000	19,469,000	19,469,000	19,469,000	$ 19,756,000
Trust preferred securities | Pooled Trust Preferred Securities Xiii [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments in pooled trust preferred securities, cost basis			1,117,000	1,117,000	1,117,000	1,117,000
Available-for-sale securities, net proceeds				1,213,000
Available-for-sale securities, gross realized gain (loss)				96,000
Heritage Financial Group
Schedule of Available-for-sale Securities [Line Items]
Investments in pooled trust preferred securities, cost basis			$ 7,231,000	7,231,000	$ 7,231,000	$ 7,231,000
Available-for-sale securities, net proceeds				7,231,000
Available-for-sale securities, gross realized gain (loss)				$ 0