Share-Based Compensation - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Compensation expense	$ 2.9	$ 2.7	$ 5.3
Unrecognized compensation expense	$ 4.2
Shares expected to be surrendered by employees	197,000
Surrender of common stock by employees	99,920
November 2015
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Estimated forfeiture rate	8.50%
November 2014
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Estimated forfeiture rate	10.30%
November 2013
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Estimated forfeiture rate	8.20%
Fourth Amendment And Restated Equity Incentive Plan
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Authorized shares available for issuance	1,279,573