Related-party Arrangements - Additional Information (Detail) (USD $)	1 Months Ended					12 Months Ended			263 Months Ended			1 Months Ended					12 Months Ended		1 Months Ended	12 Months Ended			24 Months Ended				3 Months Ended		12 Months Ended		24 Months Ended	1 Months Ended
	Dec. 31, 2012	Oct. 31, 2012	May 31, 2012	May 17, 2012	Oct. 31, 2007	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012	Jun. 27, 2012	Feb. 08, 2012	Oct. 31, 2012 Loan Arrangement	Aug. 31, 2010 Letter Agreement	Aug. 05, 2005 Private Placement	Oct. 31, 2012 Warrant Private Placement	Oct. 31, 2012 Restricted Stock Private Placement	Dec. 31, 2012 Maximum	Dec. 31, 2012 Minimum	Aug. 10, 2010 Mann Group	Dec. 31, 2011 Mann Group	Mar. 31, 2011 Mann Group	Dec. 31, 2010 Mann Group	Dec. 31, 2011 Mann Group	Dec. 31, 2012 Mann Group	Oct. 31, 2012 Mann Group	Oct. 31, 2012 Mann Group Warrant	Mar. 31, 2011 Seaside Eight Eight Limited Partnership	Dec. 31, 2010 Seaside Eight Eight Limited Partnership	Mar. 31, 2011 Seaside Eight Eight Limited Partnership	Dec. 31, 2010 Seaside Eight Eight Limited Partnership	Dec. 31, 2011 Seaside Eight Eight Limited Partnership	Feb. 28, 2009 Related Party Debt	Oct. 31, 2012 Related Party Debt Loan Arrangement
Related Party Transaction [Line Items]
Loan agreement with related party					$ 350,000,000
Interest rate (LIBOR)	5.00%					5.00%			5.00%				5.00%																			3.00%	5.00%
Description of variable rate interest	annual interest rate on all outstanding principal to the one-year London Interbank Offered Rate (LIBOR) on December 31, 2012 plus 5%, effective January 1, 2013											annual interest rate on all outstanding principal to the one-year LIBOR rate on December 31, 2012 plus 5%, effective beginning on January 1, 2013	One-year LIBOR																			One-year London Interbank Offered Rate (LIBOR)	One-year LIBOR
Borrowing rate																	4.50%
Promissory note maturity date	Jan. 01, 2014											Jan. 01, 2014
Principal amount outstanding under credit facility	119,600,000					119,600,000			119,600,000
Amount available for future borrowings	125,400,000					125,400,000			125,400,000
Amount prepaid for cancellation of indebtedness																	200,000,000
Number of months advances outstanding																		12 months
Related party transaction prepayment period						90 days
Closing bid price of common stock																			$ 7.15
Cancellation of principal on note payable to related party						184,537,000	11,116,000	16,681,000	212,334,000										350,000,000		27,800,000
Common stock issued and sold														17,132,000						1,400,000	1,400,000	2,100,000	3,500,000				1,400,000	2,100,000	1,400,000	2,100,000	3,500,000
Net proceeds from issuance of common stock									3,900,000											11,100,000		16,700,000	11,100,000				9,700,000	14,100,000	9,700,000	14,100,000	23,800,000
Underwritten public offering											86,300,000
Unit sold composition description											Each unit consisting of one share of common stock and a warrant to purchase 0.6 of a share of common stock
Common stock warrant to purchase of share											0.6
Restricted Stock Agreed to be Purchased by Lender											77,200,000													107,400,000	107,400,000
Authorized shares under common stock purchase agreement	350,000,000		250,000,000	250,000,000
Proposal to increase the authorized share	550,000,000		350,000,000	350,000,000		550,000,000	250,000,000		550,000,000
Capital stock authorized	286,035,082					286,035,082	131,522,945		286,035,082	31,250,000														31,250,000
Net proceeds from public offering		92,000,000
Number of shares in each units issued		1
Warrants holder exercisable ratio per common stock		0.75
Selling price of restricted shares																									$ 2.59
Amended and restated promissory note outstanding principal amount																									350,000,000
Underwritten public offering		40,000,000													40,000,000	40,000,000
Restricted warrants sale price																										$ 0.125
Accrued interest of related party debt	2,200,000					2,200,000	5,900,000		2,200,000
Available borrowings under loan agreement	12,750,000	125,400,000				12,750,000	45,000,000		12,750,000
Interest expense on note payable to related party						10,491,000	10,883,000	10,249,000	38,825,000
Expenses related to charter service on behalf of principal stockholders						$ 200,000	$ 111,000	$ 230,000