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
	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