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Allowance for Doubtful Accounts | 12 Months Ended
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Dec. 31, 2011
Allowance for Doubtful Accounts [Abstract] |
Allowance for Doubtful Accounts | 4. Allowance for Doubtful Accounts Activity in the allowance for doubtful accounts for the years ended December 31, 2011, 2010 and 2009 was as follows:
|  | 2011 |  |  | 2010 |  |  | 2009 |
|  | (In thousands) |
Balance, January 1 |  | $ | 681 |  |  | $ | 372 |  |  | $ | 366 |
Provision charged to operations: |  |  |  |  |  |  |  |  |  |  |  |
Additions to the reserve |  |  | 71 |  |  |  | 309 |  |  |  | 37 |
Collections of previously reserved accounts |  |  | (359 | ) |  |  | — |  |  |  | (31 | )
Total charged (credited) to operations |  |  | (288 | ) |  |  | 309 |  |  |  | 6 |
Non-recoverable balances written off |  |  | — |  |  |  | — |  |  |  | — |
Balance, December 31 |  | $ | 393 |  |  | $ | 681 |  |  | $ | 372 |

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