Changes in Stock Appreciation Rights (Detail) (SARs, USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
SARs
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
SAR's Granted			500				260,125
SAR's Exercised	220,874	[1]	16,000	[1]	376,362	[2]	16,000	[2]
SAR's Forfeited					5,346		1,598
Weighted Average Base Price, Granted			$ 9.84				$ 9.23
Weighted Average Base Price, Exercised	$ 7.59	[1]	$ 8.41	[1]	$ 12.43	[2]	$ 8.41	[2]
Weighted Average Base Price, Forfeited					$ 9.95		$ 10.54
Weighted Average Grant Date Fair Value, Granted			$ 5.23				$ 4.89
Restricted stock awards, closing price	$ 4.55	[1]	$ 4.96	[1]	$ 7.46	[2]	$ 4.96	[2]
Weighted Average Grant Date Fair Value, Forfeited					$ 5.39		$ 5.83

[1] The exercise of SARs listed in this table resulted in the issuance of 55,619 shares of ICG’s Common Stock during the three months ended September 30, 2013.

[2] The exercise of SARs listed in this table resulted in the issuance of 99,851 shares of ICG’s Common Stock during the nine months ended September 30, 2013.