Convertible Debt and Notes Payable (Details)			3 Months Ended		9 Months Ended		40 Months Ended
		Oct. 10, 2014 USD ($)	Sep. 30, 2016 USD ($) letters_of_credit	Sep. 30, 2015 USD ($)	Sep. 30, 2016 USD ($) letters_of_credit	Sep. 30, 2015 USD ($)	Jan. 31, 2014 USD ($)	Sep. 29, 2016 USD ($)	Jan. 31, 2016	Dec. 31, 2015 USD ($)	Mar. 10, 2014 USD ($) $ / shares
Debt and Capital Lease Obligations [Line Items]
Interest Expense, Lessee, Assets under Capital Lease			$ 100,000	$ 100,000
Components of short-term borrowings and other debt
Convertible debt	[1]		128,065,000		$ 128,065,000					$ 122,401,000
Note payable			61,145,000		61,145,000					60,831,000
Other Notes Payable			15,166,000		15,166,000					0
Revolver			0		0					5,000,000
Capital lease obligations			2,046,000		2,046,000					2,734,000
Debt, Long-term and Short-term, Combined Amount			206,422,000		206,422,000					190,966,000
Amortization of debt discount					5,107,000	$ 4,674,000
Capital Lease Obligations Incurred							$ 7,600,000
Capital Leases, Income Statement, Interest Expense			100,000	100,000	100,000	100,000
Future minimum lease payments for capital lease obligations
2016			235,000		235,000
2017			938,000		938,000
2018			938,000		938,000
2019			78,000		78,000
2020			0		0
Thereafter			0		0
Subtotal			2,189,000		2,189,000
Less: Amount representing interest	[2]		(143,000)		(143,000)
Capital lease obligations			$ 2,046,000		$ 2,046,000					2,734,000
Number of Letters of Credit | letters_of_credit			9		9
Restricted Cash and Cash Equivalents			$ 13,783,000		$ 13,783,000					10,085,000
Revolving Credit Facility
Components of short-term borrowings and other debt
Letter of credit, max borrowing capacity			25,000,000		$ 25,000,000			$ 25,000,000
Line of Credit Facility, Current Borrowing Capacity								$ 15,000,000
Line of Credit Facility, Commitment Fee Percentage					3.00%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage					0.38%
Interest Expense, Debt			$ 100,000	200,000	$ 400,000	200,000
Minimum
Components of short-term borrowings and other debt
Capital Lease Obligation, Initial Term					48 months
Capital leases, interest rate			0.60%		0.60%
Maximum
Components of short-term borrowings and other debt
Capital Lease Obligation, Initial Term					60 months
Capital leases, interest rate			6.03%		6.03%
Cash Convertible Note Economic Hedge And Warrant Transaction
Components of short-term borrowings and other debt
Cash convertible note hedge transaction						20,500,000
Treasury Stock
Components of short-term borrowings and other debt
Cash convertible note hedge transaction						300,000
Letter of Credit, NY Office 1, Expires May 2017 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, max borrowing capacity			$ 355,000		$ 355,000
Letter of Credit, NY Office 2, Expires May 2017 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, max borrowing capacity			70,000		70,000
Letter of Credit, NY Office 3, Expires October 2016 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, max borrowing capacity			695,000		695,000
Letter of Credit, NY Office 4, Expires October 2016 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, max borrowing capacity			3,373,000		3,373,000
Letter of Credit, NY Office 5, Expires November 2016 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, max borrowing capacity			1,600,000		1,600,000
Letter of Credit, San Francisco Office, Expires January 2017 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, max borrowing capacity			710,000		710,000
Letter of Credit, Connecticut Office, Expires January 2017 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, max borrowing capacity			65,000		65,000
Letter of Credit, NY Office, Expires February 2017 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, max borrowing capacity			1,000,000		1,000,000
Letter of Credit, Boston Office, Expires March 2017 | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, max borrowing capacity			382,000		382,000
Convertible Debt
Components of short-term borrowings and other debt
Note payable											$ 149,500,000
Interest rate											3.00%
Principal amount of notes being converted											$ 1,000
Interest on Convertible Debt, Net of Tax			1,100,000	1,100,000	3,400,000	3,400,000
Debt Instrument, Convertible, Conversion Price | $ / shares											$ 5.33
Convertible debt, unamortized discount			19,600,000		19,600,000					$ 24,700,000	$ 35,700,000
Amortization of debt discount			1,700,000	1,600,000	5,100,000	4,700,000
Debt Instrument, Interest Rate, Effective Percentage											8.89%
Debt Issuance Cost					3,700,000
Repayments on long-term and short-term borrowings
2016			0		0
2017			4,485,000		4,485,000
2018			4,485,000		4,485,000
2019			151,743,000		151,743,000
2020			0		0
Thereafter			0		0
Subtotal			160,713,000		160,713,000
Less: Amount representing interest	[2]		(32,648,000)		(32,648,000)
Senior Notes
Components of short-term borrowings and other debt
Notes Payable			61,145,000		61,145,000
Note payable		$ 63,300,000
Interest rate		8.25%
Interest on Convertible Debt, Net of Tax			1,300,000	$ 1,300,000	3,900,000	$ 3,900,000
Debt Issuance Cost		$ 2,900,000
Repayments on long-term and short-term borrowings
2016			1,304,000		1,304,000
2017			5,218,000		5,218,000
2018			5,218,000		5,218,000
2019			5,218,000		5,218,000
2020			5,218,000		5,218,000
Thereafter			68,468,000		68,468,000
Subtotal			90,644,000		90,644,000
Less: Amount representing interest	[2]		(29,499,000)		(29,499,000)
Insurance Note
Components of short-term borrowings and other debt
Other Notes Payable			400,000		400,000
Interest rate									1.38%
Debt Instrument, Periodic Payment, Principal					200,000
Short-term Debt, Maximum Amount Outstanding During Period					2,000,000
Repayments on long-term and short-term borrowings
2016			1,221,000		1,221,000
2017			4,225,000		4,225,000
2018			2,225,000		2,225,000
2019			3,702,000		3,702,000
2020			1,805,000		1,805,000
Thereafter			4,723,000		4,723,000
Subtotal			17,901,000		17,901,000
Less: Amount representing interest	[2]		(2,735,000)		(2,735,000)
Aircraft
Components of short-term borrowings and other debt
Other Notes Payable			14,800,000		14,800,000
Interest Expense, Debt			200,000		500,000
Aircraft | Minimum
Components of short-term borrowings and other debt
Interest rate									4.80%
Aircraft | Maximum
Components of short-term borrowings and other debt
Interest rate									7.25%
Letter of Credit Reinsurance Agreement | Letter of Credit
Components of short-term borrowings and other debt
Letter of credit, max borrowing capacity			$ 5,500,000		$ 5,500,000
Common Stock Class A
Components of short-term borrowings and other debt
Class of Warrant, Exercise Price of Warrants or Rights | $ / shares											$ 7.18

[1] The carrying amount of the convertible debt includes an unamortized discount of $19.6 million and $24.7 million as of September 30, 2016 and December 31, 2015.

[2] Amount necessary to reduce net minimum payments to present value calculated at the Company's implicit rate at inception. This amount also includes the unamortized discount on the convertible debt.