Investments - Narrative (Details) - USD ($)		3 Months Ended		9 Months Ended
	Nov. 01, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Debt securities		$ 213,424,000		$ 213,424,000
Realized losses from the sale of available-for-sale securities (less than)		100,000	$ 5,300,000	100,000	$ 5,300,000
Proceeds from sales of available-for-sale securities		74,900,000	182,700,000	83,300,000	323,700,000
Proceeds from maturity of available-for-sale securities		0	$ 0	185,000,000	$ 310,000,000
Unrealized losses		717,000		717,000		$ 1,117,000
U.S. Treasury Securities
Schedule of Available-for-sale Securities [Line Items]
U.S. Treasury securities		99,700,000		99,700,000
Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Debt securities		113,700,000		113,700,000
Unrealized losses		622,000		622,000		981,000
Preferred stock
Schedule of Available-for-sale Securities [Line Items]
Preferred stock investments		23,200,000		23,200,000
Unrealized losses		95,000		95,000		$ 57,000
Sears Holdings Corp or affiliates | Corporate debt securities
Schedule of Available-for-sale Securities [Line Items]
Debt securities		9,100,000		9,100,000
Sears Holdings Corp or affiliates | Preferred stock
Schedule of Available-for-sale Securities [Line Items]
Preferred stock investments		$ 200,000		$ 200,000
Required percent of investment account held in cash or cash equivalents | Minimum
Schedule of Available-for-sale Securities [Line Items]
Investments, target portfolio allocations				50.00%
Other aggregated investments | Minimum | Securities of any one issuer (excluding the U.S. Government)
Schedule of Available-for-sale Securities [Line Items]
Investments, portfolio allocations requiring additional consent				10.00%
Other aggregated investments | Maximum | Securities of any one issuer (excluding the U.S. Government)
Schedule of Available-for-sale Securities [Line Items]
Investments, target portfolio allocations				15.00%
Investments, portfolio allocations requiring additional consent				15.00%
Investor | Fairholme Capital Management, L.L.C.
Schedule of Available-for-sale Securities [Line Items]
Common stock ownership percentage		32.30%		32.30%
Subsequent Event | Required percent of investment account held in cash or cash equivalents | Minimum
Schedule of Available-for-sale Securities [Line Items]
Investments, target portfolio allocations	25.00%
Subsequent Event | Other aggregated investments | Maximum | Single Issuer, exchange-traded common equities
Schedule of Available-for-sale Securities [Line Items]
Investments, target portfolio allocations	5.00%
Subsequent Event | Common stock investments | Maximum
Schedule of Available-for-sale Securities [Line Items]
Investments, target portfolio allocations, amount	$ 100,000,000.0
Subsequent Event | Common, preferred or other equity investments | Maximum
Schedule of Available-for-sale Securities [Line Items]
Investments, target portfolio allocations	25.00%