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Acquisitions - Additional Information (Details) (USD $) | 3 Months Ended | 12 Months Ended | 0 Months Ended | 3 Months Ended | 12 Months Ended | 0 Months Ended | 12 Months Ended
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Dec. 31, 2013 | Sep. 30, 2013 | Jun. 30, 2013 | Mar. 31, 2013 | Dec. 31, 2012 | Sep. 30, 2012 | Jun. 30, 2012 | Mar. 31, 2012 | Dec. 31, 2013 | Dec. 31, 2012 | Dec. 31, 2011 | Oct. 02, 2013 West Williston Acquisition [Member] acre seller | Dec. 31, 2013 West Williston Acquisition [Member] | Dec. 31, 2013 West Williston Acquisition [Member] | Sep. 26, 2013 East Nesson [Member] acre | Dec. 31, 2013 East Nesson [Member]
Business Acquisition [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Consideration transferred |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 1,496,369,000 |  | $ 57,235,000
Number of sellers |  |  |  |  |  |  |  |  |  |  |  | 2 |  |  |  |
Acres acquired |  |  |  |  |  |  |  |  |  |  |  | 136,000 |  |  | 25,000 |
Recognized identifiable assets acquired |  |  |  |  |  |  |  |  |  |  |  |  | 1,496,369,000 | 1,496,369,000 |  | 57,235,000
Acquisition costs |  |  |  |  |  |  |  |  |  |  |  |  | 2,000,000 |  |  |
Investment Commitment | 7,000,000 |  |  |  |  |  |  |  | 7,000,000 |  |  |  |  |  | 8,200,000 |
Revenues | 333,615,000 | 305,498,000 | 254,582,000 | 248,304,000 | 214,327,000 | 184,710,000 | 149,063,000 | 138,566,000 | 1,141,999,000 | 686,668,000 | 330,422,000 |  | 57,600,000 |  |  |
Operating income | $ 122,133,000 | $ 150,862,000 | $ 113,450,000 | $ 117,953,000 | $ 86,619,000 | $ 72,038,000 | $ 60,184,000 | $ 58,152,000 | $ 504,398,000 | $ 276,993,000 | $ 152,567,000 |  | $ 14,900,000 |  |  |

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- Definition This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 25 -Paragraph 23 -URI http://asc.fasb.org/extlink&oid=21917927&loc=d3e1043-128460 + Details
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- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6578-128477 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 30 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6911251&loc=d3e6613-128477 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=7488404&loc=d3e6927-128479 + Details
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