Debt (Details) - USD ($)			1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 23, 2015	Jun. 17, 2015	Jul. 31, 2012	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Aug. 31, 2014	Apr. 07, 2014	Feb. 04, 2011
Debt Instrument [Line Items]
Outstanding debt				$ 356,719,000		$ 356,719,000		$ 299,956,000
Interest payments				$ 2,000,000	$ 100,000	24,000,000	$ 7,600,000
Stated interest rate (percent)	6.00%
Accrued interest paid	$ 1,500,000
Cash payments of notes payable						$ 53,163,000	$ 5,421,000
Line of Credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity										$ 105,000,000
Conditional maximum borrowing capacity										175,000,000
Swing line maximum borrowing capacity										30,000,000
TPG Aviator, L.P. [Member]
Debt Instrument [Line Items]
Repurchase amount		$ 20,000,000.0
Ownership percentage (percent)		41.00%
Cash payments of notes payable		$ 20,000,000.0
JPMorgan Chase Bank, N.A. [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity										$ 65,000,000
Citibank N.A. [Member] | Line of Credit [Member]
Debt Instrument [Line Items]
Maximum borrowing capacity									$ 40,000,000
7.50% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate (percent)				7.50%		7.50%		7.50%
Line of Credit [Member] | Senior Credit Facility [Member]
Debt Instrument [Line Items]
Outstanding debt				$ 30,000,000		$ 30,000,000		$ 0
Senior Convertible Debt [Member] | 7.50% Notes [Member]
Debt Instrument [Line Items]
Outstanding debt				46,793,000		46,793,000		55,481,000
Stated interest rate (percent)											7.50%
Aggregate principal amount											$ 100,000,000.0
Repurchase amount	8,700,000
Senior Exchange Convertible Debt [Member] | 7.50% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate (percent)			7.50%
Principal amount of debt retired			$ 44,500,000
Senior Exchange Convertible Debt [Member] | 7.50% Senior Exchange Convertible Notes [Member]
Debt Instrument [Line Items]
Outstanding debt				0		0		44,475,000
Stated interest rate (percent)			7.50%
Aggregate principal amount			$ 0
Exchanged amount	15,400,000
Repurchase amount	$ 20,500,000
Senior Notes [Member] | 8.5% Senior Notes Due 2019 [Member]
Debt Instrument [Line Items]
Outstanding debt				$ 200,000,000		$ 200,000,000		200,000,000
Stated interest rate (percent)				8.50%	8.50%	8.50%	8.50%
Aggregate principal amount					$ 200,000,000		$ 200,000,000
Senior Notes [Member] | 6.00% Senior Convertible Notes Due 2020 [Member]
Debt Instrument [Line Items]
Outstanding debt				$ 79,926,000		$ 79,926,000		$ 0
Stated interest rate (percent)	6.00%
Aggregate principal amount	$ 80,000,000
Proceeds from notes	64,500,000
Repurchase amount	$ 30,700,000