Income Taxes - Significant Components of Deferred Taxes (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets:
Real estate	$ 69,594	$ 79,244
Employee benefits	15,752	17,352
Net operating loss carryforwards	13,827	3,012
Deferred Tax Assets, Oil And Gas Properties	5,510	0
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	3,620	0
Income producing properties	0	364
Oil and gas percentage depletion carryforwards	3,616	3,471
Accruals not deductible until paid	911	1,111
Deferred Tax Assets, Other	139	0
Gross deferred tax assets	112,969	104,554
Valuation allowance	(97,068)	(384)
Deferred tax asset net of valuation allowance	15,901	104,170
Deferred Tax Liabilities:
Oil and gas properties	0	(49,905)
Undeveloped land	(7,588)	(4,937)
Convertible debt	(6,516)	(7,816)
Income producing properties	(2,257)	0
Timber	(577)	(888)
Gross deferred tax liabilities	16,938	63,546
Deferred Tax Liabilities, Net	(1,037)	0
Deferred Tax Assets, Net	$ 0	$ 40,624