Future Minimum Rentals on Non-cancelable Sales Type Leases by Years (Detail) (USD $)	Jun. 30, 2012	Dec. 31, 2011
Sale Leaseback Transaction [Line Items]
2013	$ 35,558,920
2014	32,733,408
2015	26,252,595
2016	26,220,974
2017	26,220,974
Thereafter	247,715,682
Total	$ 394,702,553	$ 415,796,738

Amount of minimum lease payments to be received by the lessor for capital leases.

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