The value of the financial instrument(s) that the original debt is being converted into in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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Debt Obligations, net (Unsecured Notes Narrative) (Details) - USD ($) shares in Millions		1 Months Ended			3 Months Ended		6 Months Ended
	Apr. 12, 2017	Mar. 31, 2017	Nov. 30, 2016	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Debt Instrument [Line Items]
Repayments of debt							$ 626,492,000	$ 991,184,000
Loss on early extinguishment of debt, net					$ 3,315,000	$ 1,457,000	3,525,000	$ 1,582,000
6.00% senior notes
Debt Instrument [Line Items]
Debt instrument, face amount					$ 375,000,000.0		$ 375,000,000.0
Stated interest rates (as a percent)					6.00%		6.00%
5.85% senior notes
Debt Instrument [Line Items]
Stated interest rates (as a percent)					5.85%		5.85%
Repayments of debt		$ 99,700,000
9.00% senior notes
Debt Instrument [Line Items]
Stated interest rates (as a percent)	9.00%				9.00%		9.00%
Repayments of debt	$ 275,000,000
5.875% senior notes
Debt Instrument [Line Items]
Stated interest rates (as a percent)						5.875%		5.875%
Repayments of debt				$ 261,400,000
6.50% senior notes
Debt Instrument [Line Items]
Debt instrument, face amount						$ 275,000,000		$ 275,000,000
Stated interest rates (as a percent)					6.50%	6.50%	6.50%	6.50%
3.875% senior notes
Debt Instrument [Line Items]
Repayments of debt				265,000,000
Loss on early extinguishment of debt, net					$ 3,100,000	$ 400,000	$ 3,100,000	$ 400,000
2015 $250 Million Secured Revolving Credit Facility
Debt Instrument [Line Items]
Debt instrument, face amount					$ 250,000,000		$ 250,000,000
Repayments of debt				$ 5,000,000
3.00% senior convertible notes
Debt Instrument [Line Items]
Stated interest rates (as a percent)			3.00%
Repayments of debt			$ 200,000,000
Conversion of senior unsecured convertible notes into common stock			$ 9,600,000
Shares of common stock converted (in shares)			0.8