Securities - (Details Textual)	3 Months Ended
	Mar. 31, 2016 USD ($) security institution	Jun. 30, 2015 security	Jun. 30, 2014 security	Dec. 31, 2015 USD ($)
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 649,237,000
Number of securities, return to accrual status | security	1	1	1
Securities available for sale, at fair value	$ 653,444,000			$ 646,805,000
Number of securities representing interests in tranches of trusts (tranches) | security	3	3
Number of institutions issuing debt | institution	250
Trust preferred securities
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	$ 24,732,000			24,770,000
Securities available for sale, at fair value	18,947,000			19,469,000
Impairments	0
Secure government, public and trust deposits
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities pledged as collateral	703,158,000			679,492,000
Short-term borrowings
Schedule of Available-for-sale Securities [Line Items]
Available for sale securities pledged as collateral	40,755,000			39,275,000
Trust preferred securities
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, at fair value	18,947,000			$ 19,469,000
Trust preferred securities | Pooled Trust Preferred Securities Xiii
Schedule of Available-for-sale Securities [Line Items]
Amortized cost	75,000
Sale proceeds	4,000
Gross loss on sales of securities available for sale	$ 71,000