Stock-Based Compensation - Summary of Activity of Non-Performance Based and Performance Based Options (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Non-Performance Based [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Under option, beginning of year, Shares	187,032	208,993	261,206
Granted, Shares
Exercised, Shares		(1,234)	(17,889)
Forfeited, Shares	(38,534)	(20,727)	(34,324)
Under option, end of year, Shares	148,498	187,032	208,993
Exercisable at end of year, Shares	148,498	182,945	207,312
Under option, beginning of year, Weighted-Average exercise Price	$ 15.32	$ 14.73	$ 13.63
Exercised, Aggregate Intrinsic Value		$ 3	$ 23
Granted, Weighted-Average exercise Price
Under option, end of year, Aggregate Intrinsic Value	1	8	26
Exercised, Weighted-Average exercise Price		$ 8.51	$ 8.49
Exercisable at end of year, Aggregate Intrinsic Value	1	8	26
Forfeited, Weighted-Average exercise Price	$ 11.28	$ 9.83	$ 9.59
Under option, end of year, Weighted-Average exercise Price	$ 16.37	$ 15.32	$ 14.73
Exercisable at end of year, Weighted-Average Excercise Price	$ 16.37	$ 13.87	$ 13.61
Under option, end of year, Weighted Average Contractual Term	3 years 4 months 2 days	4 years 4 months 21 days	4 years 2 months 16 days
Exercisable at end of year, Weighted Average Contractual Term	3 years 4 months 2 days	4 years 4 months 17 days	4 years 2 months 12 days
Performance Based [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Under option, beginning of year, Shares	393,891	441,185	485,533
Granted, Shares
Exercised, Shares		(2,468)
Forfeited, Shares	(2,570)	(44,826)	(44,348)
Under option, end of year, Shares	391,321	393,891	441,185
Exercisable at end of year, Shares	369,766	324,271	348,547
Under option, beginning of year, Weighted-Average exercise Price	$ 16.45	$ 16.43	$ 16.65
Exercised, Aggregate Intrinsic Value		4
Granted, Weighted-Average exercise Price
Under option, end of year, Aggregate Intrinsic Value	774	320	397
Exercised, Weighted-Average exercise Price		$ 9.07
Exercisable at end of year, Aggregate Intrinsic Value	$ 435	$ 128	$ 159
Forfeited, Weighted-Average exercise Price	$ 19.67	$ 16.76	$ 18.76
Under option, end of year, Weighted-Average exercise Price	$ 16.43	$ 16.45	$ 16.43
Exercisable at end of year, Weighted-Average Excercise Price	$ 17.05	$ 18.21	$ 18.16
Under option, end of year, Weighted Average Contractual Term	4 years 1 month 28 days	6 years 2 months 1 day	6 years 2 months 19 days
Exercisable at end of year, Weighted Average Contractual Term	4 years 18 days	5 years 9 months 7 days	5 years 9 months 26 days