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Securities (Details 1) (USD $) | Jun. 30, 2013 | Dec. 31, 2012
--- | --- | ---
Securities with unrealized losses aggregated by investment category and length of time |  |
Fair Value, Less than 12 Months | $ 73,782,000 | $ 33,555,000
Unrealized Loss, Less than 12 Months | (3,531,000) | (388,000)
Fair Value, 12 Months or More | 0 | 0
Unrealized Loss, 12 Months or More | 0 | 0
Fair Value | 73,782,000 | 33,555,000
Unrealized Loss | (3,531,000) | (388,000)
U.S. Government agency debt obligations [Member] |  |
Securities with unrealized losses aggregated by investment category and length of time |  |
Fair Value, Less than 12 Months | 72,418,000 | 33,555,000
Unrealized Loss, Less than 12 Months | (3,527,000) | (388,000)
Fair Value, 12 Months or More | 0 | 0
Unrealized Loss, 12 Months or More | 0 | 0
Fair Value | 72,418,000 | 33,555,000
Unrealized Loss | (3,527,000) | (388,000)
Mortgage-backed securities [Member] |  |
Securities with unrealized losses aggregated by investment category and length of time |  |
Fair Value, Less than 12 Months | 0 | 0
Unrealized Loss, Less than 12 Months | 0 | 0
Fair Value, 12 Months or More | 0 | 0
Unrealized Loss, 12 Months or More | 0 | 0
Fair Value | 0 | 0
Unrealized Loss | 0 | 0
Michigan Strategic Fund bonds [Member] |  |
Securities with unrealized losses aggregated by investment category and length of time |  |
Fair Value, Less than 12 Months | 0 | 0
Unrealized Loss, Less than 12 Months | 0 | 0
Fair Value, 12 Months or More | 0 | 0
Unrealized Loss, 12 Months or More | 0 | 0
Fair Value | 0 | 0
Unrealized Loss | 0 | 0
Municipal general obligation bonds [Member] |  |
Securities with unrealized losses aggregated by investment category and length of time |  |
Fair Value, Less than 12 Months | 0 | 0
Unrealized Loss, Less than 12 Months | 0 | 0
Fair Value, 12 Months or More | 0 | 0
Unrealized Loss, 12 Months or More | 0 | 0
Fair Value | 0 | 0
Unrealized Loss | 0 | 0
Municipal revenue bonds [Member] |  |
Securities with unrealized losses aggregated by investment category and length of time |  |
Fair Value, Less than 12 Months | 0 | 0
Unrealized Loss, Less than 12 Months | 0 | 0
Fair Value, 12 Months or More | 0 | 0
Unrealized Loss, 12 Months or More | 0 | 0
Fair Value | 0 | 0
Unrealized Loss | 0 | 0
Mutual funds [Member] |  |
Securities with unrealized losses aggregated by investment category and length of time |  |
Fair Value, Less than 12 Months | 1,364,000 | 0
Unrealized Loss, Less than 12 Months | (4,000) | 0
Fair Value, 12 Months or More | 0 | 0
Unrealized Loss, 12 Months or More | 0 | 0
Fair Value | 1,364,000 | 0
Unrealized Loss | $ (4,000) | $ 0

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- Definition This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563 + Details
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