Subsequent Events (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Oct. 05, 2016
Subsequent Event [Line Items]
Proceeds from Sale of Buildings and Land				$ 142,808	$ 243,943
Loss on debt extinguishment		$ 3,494	$ 0	$ 3,494	$ 0
Unsecured Debt [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Loss on debt extinguishment	$ 23,300
6.625% Senior Note [Member] | Senior Notes [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Interest rate on notes						6.625%
Debt amount to be repurchased						$ 296,500
7.5% Medium Term Note [Member] | Medium-term Notes [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Interest rate on notes						7.50%
Debt amount to be repurchased						$ 100,000