Deferred Charges (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Deferred charges
Deferred charges-cost, beginning of the year	$ 25,377	$ 23,566
Additions	11,696	3,248
Write-offs due to extinguishment of debt	(16,995)
Write-offs due to amendment and restatement of revolving credit facility		(1,437)
Deferred charges-cost, end of the year	20,078	25,377	23,566
Accumulated amortization, beginning of the year	(10,957)	(8,384)
Amortization during the year	(3,354)	(3,411)	(3,942)
Write-offs due to extinguishment of debt	8,873
Write-offs due to amendment and restatement of revolving credit facility		838
Accumulated amortization, end of the year	(5,438)	(10,957)	(8,384)
Net book value	14,640	14,420
Life in years, minimum	3 years	1 year
Life in years, maximum	5 years	5 years
Amortization expense
Amortization expense	$ 3,354	$ 3,411	$ 3,942