Investments in Unconsolidated Affiliates - Combined Financial Information of Unconsolidated Affiliated Companies (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Assets:
Current assets	$ 47,866		$ 47,866
Noncurrent assets	147,574		147,574
Total assets	195,440		195,440
Liabilities:
Current liabilities	44,234		44,234
Noncurrent liabilities	73,994		73,994
Total liabilities	118,228		118,228
Results of operations:
Revenue	52,526	50,927	111,260	105,575
Net income (loss)	$ 3,796	$ 9,591	$ (6,702)	$ (4,036)