| Schedule of Net Benefit Costs [Table Text Block] |
| | Three Months Ended September 30, 2012 | | | Three Months Ended September 30, 2011 | | | | BMP, Employee and Outside Director Retirement Plans | | | | | | BMP, Employee and Outside Director Retirement Plans | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Actuarial adjustment to prior period interest cost and amortization | | | | | | | | | | | | | | | | | Expected return on assets | | | | ) | | | | | | | | ) | | | | | Unrecognized past service liability | | | | | | | | | | | | | | | | | Amortization of unrealized loss | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
| | Nine Months Ended September 30, 2012 | | | Nine Months Ended September 30, 2011 | | | | BMP, Employee and Outside Director Retirement Plans | | | | | | BMP, Employee and Outside Director Retirement Plans | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Actuarial adjustment to prior period interest cost and amortization | | | | | | | | | | | | | | | | | Expected return on assets | | | | ) | | | | | | | | ) | | | | | Unrecognized past service liability | | | | | | | | | | | | | | | | | Amortization of unrealized loss | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
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