Stock-Based Compensation - Information about Stock Options Outstanding Under All Stock Plans (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range of exercise prices	$ 5.50
Upper range of exercise prices	$ 11.84
Options Outstanding, Number	1,531,184
Options Outstanding, Weighted Average Contractual Life (Years)	4 years 26 days
Options Outstanding, Weighted Average Exercise Price	$ 8.40
Options Exercisable, Number	823,251
Options Exercisable, Weighted Average Exercise Price	$ 9.46
Range One [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range of exercise prices	$ 5.50
Upper range of exercise prices	$ 6.86
Options Outstanding, Number	88,574
Options Outstanding, Weighted Average Contractual Life (Years)	4 years 10 months 10 days
Options Outstanding, Weighted Average Exercise Price	$ 6.62
Options Exercisable, Number	62,278
Options Exercisable, Weighted Average Exercise Price	$ 6.72
Range Two [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range of exercise prices	$ 6.87
Upper range of exercise prices	$ 7.93
Options Outstanding, Number	756,648
Options Outstanding, Weighted Average Contractual Life (Years)	5 years 11 months 27 days
Options Outstanding, Weighted Average Exercise Price	$ 7.26
Options Exercisable, Number	78,511
Options Exercisable, Weighted Average Exercise Price	$ 7.73
Range Three [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range of exercise prices	$ 8.07
Upper range of exercise prices	$ 8.63
Options Outstanding, Number	40,045
Options Outstanding, Weighted Average Contractual Life (Years)	2 years 8 months 16 days
Options Outstanding, Weighted Average Exercise Price	$ 8.48
Options Exercisable, Number	38,045
Options Exercisable, Weighted Average Exercise Price	$ 8.48
Range Four [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range of exercise prices	$ 8.76
Upper range of exercise prices	$ 8.76
Options Outstanding, Number	43,000
Options Outstanding, Weighted Average Contractual Life (Years)	2 years 4 months 10 days
Options Outstanding, Weighted Average Exercise Price	$ 8.76
Options Exercisable, Number	43,000
Options Exercisable, Weighted Average Exercise Price	$ 8.76
Range Five [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range of exercise prices	$ 8.96
Upper range of exercise prices	$ 9.09
Options Outstanding, Number	101,500
Options Outstanding, Weighted Average Contractual Life (Years)	1 year 10 months 28 days
Options Outstanding, Weighted Average Exercise Price	$ 9.09
Options Exercisable, Number	100,000
Options Exercisable, Weighted Average Exercise Price	$ 9.09
Range Six [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range of exercise prices	$ 9.11
Upper range of exercise prices	$ 9.12
Options Outstanding, Number	6,627
Options Outstanding, Weighted Average Contractual Life (Years)	2 years 8 months 23 days
Options Outstanding, Weighted Average Exercise Price	$ 9.11
Options Exercisable, Number	6,627
Options Exercisable, Weighted Average Exercise Price	$ 9.11
Range Seven [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range of exercise prices	$ 9.16
Upper range of exercise prices	$ 9.16
Options Outstanding, Number	132,000
Options Outstanding, Weighted Average Contractual Life (Years)	2 years 10 months 2 days
Options Outstanding, Weighted Average Exercise Price	$ 9.16
Options Exercisable, Number	132,000
Options Exercisable, Weighted Average Exercise Price	$ 9.16
Range Eight [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range of exercise prices	$ 9.19
Upper range of exercise prices	$ 10.25
Options Outstanding, Number	121,780
Options Outstanding, Weighted Average Contractual Life (Years)	2 years 5 months 12 days
Options Outstanding, Weighted Average Exercise Price	$ 9.70
Options Exercisable, Number	121,780
Options Exercisable, Weighted Average Exercise Price	$ 9.70
Range Nine [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range of exercise prices	$ 10.46
Upper range of exercise prices	$ 11.00
Options Outstanding, Number	100,960
Options Outstanding, Weighted Average Contractual Life (Years)	1 year 2 months 16 days
Options Outstanding, Weighted Average Exercise Price	$ 10.72
Options Exercisable, Number	100,960
Options Exercisable, Weighted Average Exercise Price	$ 10.72
Range Ten [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Lower range of exercise prices	$ 11.01
Upper range of exercise prices	$ 11.84
Options Outstanding, Number	140,050
Options Outstanding, Weighted Average Contractual Life (Years)	3 months 22 days
Options Outstanding, Weighted Average Exercise Price	$ 11.56
Options Exercisable, Number	140,050
Options Exercisable, Weighted Average Exercise Price	$ 11.56