Investment Securities (Details Textual)	1 Months Ended	12 Months Ended
	Feb. 28, 2014 Security	Dec. 31, 2015 USD ($) Security Investment	Dec. 31, 2014 USD ($) Security	Dec. 31, 2013 USD ($) Security	Jan. 14, 2014 USD ($)
Schedule Of Available For Sale Securities [Line Items]
Trading securities (Note 2)		$ 8,134,000	$ 7,861,000
Carrying value of investment securities for pledge		$ 108,200,000	$ 116,600,000
Investment securities with fair value less than amortized cost | Security		34	37
Impairment loss recognized through impairment assessment process		$ 0	$ 0
Minimum assets of trust preferred securities issued by institution					$ 15,000,000,000
Available-for-sale Securities, Amortized Cost		154,124,000	161,703,000
Total debt securities, Fair Value		153,901,000	162,247,000
Net impairment losses recognized in earnings				$ 1,954,000
Non-accrual investment securities		$ 778,000	$ 779,000
Trust preferred securities in nonaccrual status | Investment		2
Estimated length of interest payment delays		10 years
iTruPS securities
Schedule Of Available For Sale Securities [Line Items]
Number of securities owned by company | Security				9
Available-for-sale Securities, Amortized Cost				$ 10,500,000
Total debt securities, Fair Value				8,500,000
Net impairment losses recognized in earnings				$ 2,000,000
Number of securities sold by company | Security	9