Trading Securities (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	$ 188,700,000	$ 91,616,000
Trading Securities, Net Unrealized Gain (Loss)	187,000	11,000
Trading Securities Pledged as Collateral	0	0
U.S. government agency debentures [Member]
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	85,092,000	34,120,000
Trading Securities, Net Unrealized Gain (Loss)	(62,000)	77,000
U.S. government agency residential mortgage-backed securities [Member]
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	31,199,000	21,011,000
Trading Securities, Net Unrealized Gain (Loss)	269,000	123,000
Municipal and other tax-exempt securities [Member]
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	38,951,000	27,350,000
Trading Securities, Net Unrealized Gain (Loss)	18,000	(182,000)
Other trading securities [Member]
Schedule of Trading Securities [Line Items]
Trading Securities, Fair Value	33,458,000	9,135,000
Trading Securities, Net Unrealized Gain (Loss)	$ (38,000)	$ (7,000)