Sale of Discontinued Operations - Summary of Greenline's Operating Results (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on the sale of discontinued operations, net of tax benefit	$ 7,642
Income (loss) from discontinued operations	(189)	(1,715)	(1,743)
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues	6,137	7,364	9,227
Expenses	6,384	10,048	11,944
Loss before income taxes and gain on the sale from discontinued operations	(247)	(2,684)	(2,717)
Benefit for income taxes	(58)	(969)	(974)
Gain on the sale of discontinued operations, net of tax benefit	7,642
Income (loss) from discontinued operations	$ 7,453	$ (1,715)	$ (1,743)