Share Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended							3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended				1 Months Ended			9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Restructuring Charges [Member]	Sep. 30, 2013 Performance Unit Incentive Plan (PUP) [Member]	Sep. 30, 2013 Performance Unit Incentive Plan (PUP) [Member]	Sep. 30, 2012 Performance Unit Incentive Plan (PUP) [Member]	Dec. 31, 2012 Performance Unit Incentive Plan (PUP) [Member]	Sep. 30, 2013 Stock Options [Member]	Sep. 30, 2012 Stock Options [Member]	Sep. 30, 2013 Stock Options [Member]	Sep. 30, 2012 Stock Options [Member]	Sep. 30, 2013 Restricted Stock [Member]	Sep. 30, 2012 Restricted Stock [Member]	Sep. 30, 2013 Restricted Stock [Member]	Sep. 30, 2012 Restricted Stock [Member]	Sep. 30, 2013 Restricted Stock Units and Performance Based Restricted Stock Units [Member]	Dec. 31, 2012 Restricted Stock Units and Performance Based Restricted Stock Units [Member]	Jan. 31, 2012 PBRS [Member]	Feb. 28, 2013 Restricted Stock Units [Member]	Feb. 28, 2012 Restricted Stock Units [Member]	Sep. 30, 2013 Restricted Stock Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation before income tax benefit	$ 1,202,000	$ 1,670,000	$ 3,569,000	$ 4,524,000	$ 253,000	$ 94,000				$ 3,000	$ 148,000	$ 104,000	$ 450,000	$ 802,000	$ 890,000	$ 2,522,000	$ 2,610,000
Unamortized cost														4,100,000		4,100,000
Recognition Period of Unrecognized cost												1 year				1 year 10 months 24 days
Repurchase of Common Stock for Employee Tax Withholding Obligations amount			1,300,000	1,000,000
Repurchased shares tax withholding			48,937	53,019
Shares Available for Grant	1,005,372		1,005,372
Liabilities related to restricted stock																		405,000	633,000
Payments To Employees			0	0																35,000	300,000	257,000
Liability awards recorded							4,600,000		3,700,000
PUP award vested							0	0								161,186							11,300
Total unrecognized cost related to non-vested stock option awards	$ 3,000		$ 3,000
Stock options granted			0