Segment Information - Assets Allocated by Segment (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Total Assets	$ 1,143,244		$ 1,172,152
Cash and cash equivalents	147,979		192,307		86,653	10,361
Deferred tax asset, net	39,164		40,398
Operating Segments [Member] | Real estate [Member]
Segment Reporting Information [Line Items]
Total Assets	592,447		582,802
Operating Segments [Member] | Oil and gas [Member]
Segment Reporting Information [Line Items]
Total Assets	320,972		312,553
Operating Segments [Member] | Other natural resources [Member]
Segment Reporting Information [Line Items]
Total Assets	23,381		23,478
Items not allocated to segments [Member] | Assets not allocated to segments [Member]
Segment Reporting Information [Line Items]
Total Assets	$ 206,444	[1]	$ 253,319	[1]

[1] Assets not allocated to segments at first quarter-end 2014 principally consist of cash and cash equivalents of $147,979,000 and a net deferred tax asset of $39,164,000. Assets not allocated to segments at year-end 2013 principally consist of cash and cash equivalents of $192,307,000 and a net deferred tax asset of $40,398,000.