Stock Incentive Plans - Summary of Activity of Stock Incentive and Equity Plans (Detail) (USD $)	1 Months Ended								2 Months Ended			7 Months Ended	12 Months Ended
	Oct. 31, 2013	Jul. 31, 2012	Jan. 31, 2012	Dec. 31, 2011	Oct. 31, 2011	Jul. 31, 2011	May 31, 2011	Jan. 31, 2011	Oct. 31, 2012	May 31, 2012	Apr. 30, 2011	Jul. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Shares available for grant
Shares available for grant, Beginning balance			2,259,999					643,850				2,200,604	2,200,604	2,259,999	643,850
Shares available for grant, Authorized															2,100,000
Shares available for grant, Granted													(216,913)	(106,395)	(389,774)
Shares available for grant, Exercised
Shares available for grant, Expired															(139,988)
Shares available for grant, Canceled/forfeited													256,412	47,000	45,911
Shares available for grant, Ending balance				2,259,999									2,240,103	2,200,604	2,259,999
Number of options outstanding
Number of options outstanding, Beginning balance			2,093,108					1,830,397				2,117,110	2,117,110	2,093,108	1,830,397
Number of options outstanding, Authorized
Number of options outstanding, Granted	14,450	7,000	8,500	143,000	75,400	12,500	51,650	26,000	36,800	36,750	73,500	82,815	97,265	89,050	382,050
Number of options outstanding, Exercised													(27,930)	(17,885)	(73,428)
Number of options outstanding, Expired
Number of options outstanding, Canceled/forfeited													(260,375)	(47,163)	(45,911)
Number of options outstanding, Ending balance				2,093,108									1,926,070	2,117,110	2,093,108
Weighted - average option exercise price
Weighted - average option exercise price, Beginning balance			$ 13.45					$ 12.98				$ 13.32	$ 13.32	$ 13.45	$ 12.98
Weighted - average option exercise price, Authorized
Weighted - average option exercise price, Granted													$ 8.43	$ 9.72	$ 16.02
Weighted - average option exercise price, Exercised													$ 5.02	$ 4.01	$ 10.78
Weighted - average option exercise price, Expired
Weighted - average option exercise price, Canceled/forfeited													$ 18.31	$ 15.13	$ 20.15
Weighted - average option exercise price, Ending balance				$ 13.45									$ 12.46	$ 13.32	$ 13.45
Number of restricted stock shares issued
Number of restricted stock shares issued, Beginning balance			42,587					34,863				59,932	59,932	42,587	34,863
Number of restricted stock shares issued, Authorized
Number of restricted stock shares issued, Granted													73,707	17,345	7,724
Number of restricted stock shares issued, Exercised
Number of restricted stock shares issued, Expired
Number of restricted stock shares issued, Canceled/forfeited
Number of restricted stock shares issued, Ending balance				42,587									133,639	59,932	42,587
Number of restricted stock shares issued, Beginning balance												59,932	59,932
Number of restricted stock shares issued, Authorized
Number of restricted stock shares issued, Granted													45,941
Number of restricted stock shares issued, Exercised
Number of restricted stock shares issued, Expired
Number of restricted stock shares issued, Canceled/forfeited
Number of restricted stock shares issued, Ending balance													45,941	59,932