Income Taxes - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Income Tax [Line Items]
Net Valuation Allownce Change	$ 0	$ 4.5
Net Operating Loss carry forward		$ 156.0
Minimum
Income Tax [Line Items]
Tax year remain open to examination	1998
Maximum
Income Tax [Line Items]
Tax year remain open to examination	2012
Domestic Tax Authority | Minimum
Income Tax [Line Items]
Beginning of NOL Carry forward expiry date		2024
Domestic Tax Authority | Maximum
Income Tax [Line Items]
Beginning of NOL Carry forward expiry date		2032
State and Local Jurisdiction | Minimum
Income Tax [Line Items]
Beginning of NOL Carry forward expiry date		2014
State and Local Jurisdiction | Maximum
Income Tax [Line Items]
Beginning of NOL Carry forward expiry date		2032