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Significant components of U.S. deferred income tax expense (benefit) (Details) (USD $)
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12 Months Ended | ||
|---|---|---|---|
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Dec. 31, 2013
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Dec. 31, 2012
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Dec. 31, 2011
|
|
| Significant components of U.S. deferred income tax expense (benefit) | |||
| Deferred tax (benefit) expense | $ (3,209,000) | $ 10,661,000 | $ 17,774,000 |
| Net operating loss carryforward (generated) expired | (6,536,000) | 26,924,000 | 187,597,000 |
| Valuation allowance increase (decrease) | 9,745,000 | (37,585,000) | (205,371,000) |
| Provision for Income taxes | $ 0 | $ 0 | $ 0 |