| **Quarterly Financial Data (unaudited) (Tables)**         | 12 Months Ended                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
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| **Quarterly Financial Information Disclosure [Abstract]** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
| Quarterly Financial Data                                  |    Quarters Ended   December 31 September 30 June 30 March 312016       Operating revenue$18,747 $27,192 $29,551 $20,254Operating (loss) income$(881) $1,595 $2,143 $(897)Net income attributable to the Company$2,709 $2,711 $1,810 $8,665Basic and diluted income per share attributable to the Company$0.04 $0.04 $0.02 $0.112015       Operating revenue$21,104 $27,830 $37,846 $17,091Operating (loss) income$(3,861) $(2,383) $5,811 $(5,702)Net (loss) income attributable to the Company$(2,541) $2,772 $(224) $(1,738)Basic and diluted (loss) income per share attributable to the Company$(0.03) $0.03 $— $(0.02) |

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| - References
No definition available.
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| - Definition
Tabular disclosure of quarterly financial data. Includes, but is not limited to, financial information for fiscal quarters, cumulative effect of a change in accounting principle and earnings per share data.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 270 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (a)-(j) -URI http://asc.fasb.org/extlink&oid=68076893&loc=d3e1280-108306
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