Senior Notes, Secured, and Unsecured Indebtedness - Senior Notes - Narrative (Details) - USD ($)						1 Months Ended					3 Months Ended		12 Months Ended
	Mar. 09, 2018	Jan. 31, 2017	Sep. 15, 2015	Aug. 11, 2014	Mar. 31, 2014	Sep. 30, 2018	May 31, 2017	Jan. 31, 2016	Jan. 31, 2015	Aug. 31, 2014	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Mar. 08, 2018
Debt Instrument [Line Items]
Gain (Loss) on Extinguishment of Debt											$ 383,000	$ 0
Deferred loan costs											$ (14,500,000)
6% Senior Notes due September 1, 2023
Debt Instrument [Line Items]
Stated interest rate											6.00%
7% Senior Notes due August 15, 2022
Debt Instrument [Line Items]
Stated interest rate											7.00%		7.00%
5 3/4% Senior Notes due April 15, 2019
Debt Instrument [Line Items]
Stated interest rate											5.75%		5.75%
5 7/8% Senior Notes due January 31, 2025
Debt Instrument [Line Items]
Stated interest rate											5.875%		5.875%
8 1/2% Senior Notes due November 15, 2020
Debt Instrument [Line Items]
Stated interest rate											8.50%		8.50%
Senior notes | 6% Senior Notes due September 1, 2023
Debt Instrument [Line Items]
Stated interest rate	6.00%										6.00%		6.00%	6.00%
Principal amount											$ 350,000,000
Percentage of principal amount	100.00%
Percent exchanged						100.00%
Outstanding amount													$ 350,000,000
Senior notes | 7% Senior Notes due August 15, 2022
Debt Instrument [Line Items]
Stated interest rate				7.00%							7.00%		7.00%
Principal amount			$ 50,000,000.0	$ 300,000,000
Percentage of principal amount			102.00%	100.00%
Percent exchanged									100.00%
Deferred loan costs											$ (2,900,000)
Net proceeds from issuance of debt			$ 50,500,000
Expected percent exchanged								100.00%
Outstanding amount											350,000,000
Unamortized premium											$ 500,000
Senior notes | 5 3/4% Senior Notes due April 15, 2019
Debt Instrument [Line Items]
Stated interest rate					5.75%						5.75%		5.75%
Principal amount					$ 150,000,000
Percentage of principal amount					100.00%
Percent exchanged										100.00%
Deferred loan costs											$ (5,800,000)
Senior notes | 5 7/8% Senior Notes due January 31, 2025
Debt Instrument [Line Items]
Stated interest rate		5.875%									5.875%
Principal amount		$ 450,000,000
Percentage of principal amount		99.215%
Percent exchanged							100.00%
Deferred loan costs											$ (5,800,000)
Outstanding amount											437,000,000
Debt Instrument, Unamortized Discount											$ (2,700,000)
Senior notes | 8 1/2% Senior Notes due November 15, 2020
Debt Instrument [Line Items]
Stated interest rate											6.00%
Outstanding amount											$ 425,000,000
California Lyon | Senior notes | 6% Senior Notes due September 1, 2023
Debt Instrument [Line Items]
Senior Notes Redemption Price Percentage											100.00%
Redemption price, percentage													106.00%
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed													35.00%
Minimum | Senior notes | 6% Senior Notes due September 1, 2023
Debt Instrument [Line Items]
Redemption Notice Period											30 days
Maximum | Senior notes | 6% Senior Notes due September 1, 2023
Debt Instrument [Line Items]
Redemption Notice Period											60 days