Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Real Estate Acquired Through Foreclosure Under Forward Purchase Agreements [Line Items]
Income tax benefits associated with exercise of non-qualified stock options and restricted stock	$ 0.5	$ 0.1	$ 0
Increase in valuation allowance due to state net operating loss and tax credit carryforwards	0.2
Changes in Valuation allowance primarily related to NOL		0.2
State net operating loss carryforwards	29.2
State tax credit carryforwards	1.6
Unrecognized tax benefits that would impact effective tax rate	2.9
Accrued interest expense	0.3	0.2
Liability for interest expense	0.3	0.3
Liability for penalties	0.3	0.3
Accrued interest penalty		0.2
2014 Forecast [Member]
Real Estate Acquired Through Foreclosure Under Forward Purchase Agreements [Line Items]
Reductions in the liability for unrecognized tax benefits due to expiration of statues of limitation	$ 0.3