Condensed Summary of Actual Quarterly Results of Operations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information [Line Items]
Revenues	$ 183,045		$ 187,942		$ 198,909		$ 177,822		$ 173,357		$ 204,824		$ 242,745		$ 236,990		$ 747,718	$ 857,916	$ 832,022
Gross Profit	20,681		18,091		28,877		18,081		15,899		26,405		37,456		36,778		79,729	116,538	115,592
Operating Income (Loss)	8,009		(3,428)		2,130		(273)		(2,279)		8,869		19,003		18,503		6,438	44,096	49,056
Net income (loss)	1,096		(7,267)		(1,663)		(4,616)		(5,588)		30,473		13,153		11,992		(12,451)	50,030	18,590
Net Income (Loss) Attributable to Common Stockholders	$ 1,100		$ (7,267)		$ (1,662)		$ (4,614)		$ (5,584)		$ 30,501		$ 13,155		$ 12,005		$ (12,445)	$ 50,077	$ 18,605
Basic Earnings (Loss) Per Share	$ 0.04		$ (0.25)		$ (0.06)		$ (0.16)		$ (0.20)		$ 1.08		$ 0.47		$ 0.43		$ (0.44)	$ 1.77	$ 0.67
Diluted earnings (loss) per share attributable to common stockholders	$ 0.04	[1]	$ (0.25)	[1]	$ (0.06)	[1]	$ (0.16)	[1]	$ (0.20)	[1]	$ 1.07	[1]	$ 0.46	[1]	$ 0.42	[1]	$ (0.44)	$ 1.76	$ 0.66

[1] See Note 13 for discussion on the computation of diluted shares outstanding.