Pro Forma Results of Combined Company Operations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Business Acquisition, Pro Forma Information [Line Items]
Total Revenues	$ 170,390	$ 162,383
Net loss	$ (384)	$ (1,100)
Loss per share
Basic	$ (0.01)	$ (0.03)
Diluted	$ (0.01)	$ (0.03)