Discontinued Operations - Results for Discontinued Operations (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Discontinued Operations And Disposal Groups [Abstract]
Revenues	$ 468	$ 1,416	$ 1,414	$ 2,755
Operating expenses	(341)	(558)	(647)	(1,073)
Interest expense		(64)		(129)
Depreciation and amortization	(157)	(471)	(507)	(925)
Gain on sale of assets	6,752		9,527
Impairment loss	(154)		(154)
Income from discontinued operations	$ 6,568	$ 323	$ 9,633	$ 628