Incentive Compensation Plan - Unvested Target Award (Detail)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding, beginning of the year, Shares	271,000	253,000	50,060
Granted, Shares	94,626	58,000	224,000
Vested, Shares	98,487	35,000	17,060
Forfeited, Shares	(2,139)	(5,000)	(4,000)
Outstanding, end of the year, Shares	265,000	271,000	253,000
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Outstanding, beginning of the year, Shares	250,777	151,333	93,333
Granted, Shares	126,389	138,611	74,000
Vested, Shares	(12,626)	0	0
Forfeited, Shares	(80,540)	(39,167)	(16,000)
Outstanding, end of the year, Shares	284,000	250,777	151,333