Fair Value Measurements (Details 3) (USD $)	3 Months Ended
	Mar. 31, 2015 item	Mar. 31, 2014 item
Changes in the fair value of Level 3 assets measured on a recurring basis
Total gains or losses (unrealized): included in earnings	$ 0	$ 0
Number of transfers between levels	0	0
U.S. States and political subdivisions securities
Changes in the fair value of Level 3 assets measured on a recurring basis
Balance at the beginning of the period	6,466,000	5,498,000
Total gains or losses (realized/unrealized): included in earnings	0	0
Total gains or losses (realized/unrealized): included in other comprehensive income	(7,000)	16,000
Purchases	0	0
Issuances	0	0
Sales	0	0
Settlements	0	0
Maturities	(827,000)	(805,000)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance at the end of the period	5,632,000	4,709,000
Foreign government and other securities
Changes in the fair value of Level 3 assets measured on a recurring basis
Balance at the beginning of the period	811,000	0
Total gains or losses (realized/unrealized): included in earnings	0	0
Total gains or losses (realized/unrealized): included in other comprehensive income	(3,000)	0
Purchases	0	0
Issuances	0	0
Sales	0	0
Settlements	0	0
Maturities	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance at the end of the period	808,000	0
Investment securities available-for-sale
Changes in the fair value of Level 3 assets measured on a recurring basis
Balance at the beginning of the period	7,277,000	5,498,000
Total gains or losses (realized/unrealized): included in earnings	0	0
Total gains or losses (realized/unrealized): included in other comprehensive income	(10,000)	16,000
Purchases	0	0
Issuances	0	0
Sales	0	0
Settlements	0	0
Maturities	(827,000)	(805,000)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance at the end of the period	$ 6,440,000	$ 4,709,000