Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) issuer shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($)
Operating Leases, Future Minimum Payments Due
2017	$ 7,784,000
2018	7,575,000
2019	7,370,000
2020	6,729,000
2021	6,545,000
Operating Leases, Future Minimum Payments Receivable	$ 36,003,000
Percentage of certain resort fees included in management services revenues	50.00%
Temporary unrealized losses related to debt securities	$ 1,886,000	$ 1,117,000
Other-than-temporary impairment losses	0	0	$ 1,295,000
Realized gains (losses) on sale of securities	$ 795,000	5,311,000	(833,000)
Other than temporary losses, investments, portion in other comprehensive loss			$ 1,500,000
Period restricted investments are to be allocated to 401(k) plan participants	5 years		7 years
Allowance for doubtful accounts	$ 0	0
Capitalized indirect costs incurred	$ 0	$ 200,000	$ 600,000
Timber holdings valuation sample	20.00%
Cash, uninsured amount	$ 40,400,000
Debt securities, fair value	$ 139,132,000
Common stock equivalents (in shares) | shares	0	0
U.S. Treasury securities
Operating Leases, Future Minimum Payments Due
Temporary unrealized losses related to debt securities		$ 79,000
Corporate debt securities
Operating Leases, Future Minimum Payments Due
Temporary unrealized losses related to debt securities	$ 1,769,000	981,000
Debt securities, fair value	$ 139,100,000
Number of issuers | issuer	10
Preferred stock
Operating Leases, Future Minimum Payments Due
Temporary unrealized losses related to debt securities	$ 111,000	57,000
Commercial paper
Operating Leases, Future Minimum Payments Due
Debt securities, fair value	$ 129,700,000
Number of issuers | issuer	7
Other Assets | Accounting Standards Update 2015-03
Operating Leases, Future Minimum Payments Due
Debt issuance costs, net		(2,100,000)
Long-term Debt | Accounting Standards Update 2015-03
Operating Leases, Future Minimum Payments Due
Debt issuance costs, net		700,000
Senior Notes Held By Special Purpose Entity | Accounting Standards Update 2015-03
Operating Leases, Future Minimum Payments Due
Debt issuance costs, net		$ 1,400,000
External Credit Rating, Non Investment Grade | Preferred stock
Operating Leases, Future Minimum Payments Due
Other marketable securities, noncurrent	$ 36,600,000
Number of issuers | issuer	3
Land improvements | Minimum | Real Estate
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	15 years
Land improvements | Maximum | Real Estate
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	20 years
Buildings | Minimum | Real Estate
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	20 years
Buildings | Maximum | Real Estate
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	40 years
Building improvements | Minimum | Real Estate
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	5 years
Building improvements | Maximum | Real Estate
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	25 years
Railroad and equipment | Minimum
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	15 years
Railroad and equipment | Maximum
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	30 years
Furniture and fixtures | Minimum
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	5 years
Furniture and fixtures | Maximum
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	10 years
Machinery and equipment | Minimum
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	3 years
Machinery and equipment | Maximum
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	10 years
Office equipment | Minimum
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	5 years
Office equipment | Maximum
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	10 years
Autos and trucks
Operating Leases, Future Minimum Payments Due
Estimated useful life (in years)	5 years