Changes in Stock Appreciation Rights (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted Average Base Price, Outstanding, Beginning balance	$ 6.91		$ 6.25		$ 16.64
Weighted Average Base Price, Outstanding, Ending balance	$ 4.30		$ 6.91		$ 6.25
Weighted Average Fair Value, Outstanding, Beginning balance
Weighted Average Fair Value, Granted	$ 12.30		$ 9.42		$ 12.02
Weighted Average Fair Value, Exercised	$ 12.30		$ 9.42		$ 12.02
Weighted Average Fair Value, Outstanding, Ending balance
SARs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
SARs, Outstanding, Beginning balance	4,338,250		4,147,391		3,971,885
SARs, Granted	2,500		260,125		275,625
SARs, Exercised	(3,045,700)	[1]	(54,873)	[1]	(100,119)	[1]
SARs, Forfeited	(62,242)		(1,598)
SARs, Cancelled			(12,795)
SARs, Outstanding, Ending balance	1,232,808		4,338,250		4,147,391
Weighted Average Base Price, Outstanding, Beginning balance	$ 7.80		$ 7.71		$ 7.45
Weighted Average Base Price, Granted	$ 16.19		$ 9.25		$ 12.15
Weighted Average Base Price, Exercised	$ 14.42	[1]	$ 7.89	[1]	$ 9.74	[1]
Weighted Average Base Price, Forfeited	$ 10.25		$ 10.54
Weighted Average Base Price, Cancelled			$ 6.70
Weighted Average Base Price, Outstanding, Ending balance	$ 8.86		$ 7.80		$ 7.71
Weighted Average Fair Value, Outstanding, Beginning balance	$ 4.56		$ 4.54		$ 4.43
Weighted Average Fair Value, Granted	$ 9.83		$ 4.90		$ 6.58
Weighted Average Fair Value, Exercised	$ 8.64	[1]	$ 4.65	[1]	$ 5.82	[1]
Weighted Average Fair Value, Forfeited	$ 5.51		$ 5.83
Weighted Average Fair Value, Cancelled			$ 3.93
Weighted Average Fair Value, Outstanding, Ending balance	$ 4.99		$ 4.56		$ 4.54

[1] The exercise of SARs listed in this table resulted in the issuance of 992,390 shares, 9,818 shares and 20,229 shares of ICG’s Common Stock during the years ended December 31, 2013, 2012 and 2011.