Stock-Based Compensation - Additional Information (Detail) (USD $)	12 Months Ended			0 Months Ended				1 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jul. 31, 2014	Jan. 31, 2014	Jul. 31, 2013	Jan. 31, 2013	May 30, 2009	Aug. 01, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Deferred Compensation Share-based Arrangements, Liability, Current and Noncurrent	$ 500,000	$ 500,000,000	$ 500,000,000
Grants in period, weighted average grant date fair value	$ 3.09	$ 3.89
Options vested in period		0
Shares
Options outstanding Beginning Balance	281,000	201,000
Options granted	100,000	150,000	0
Options exercised	(131,000)	(69,000)
Options forfeited	(100,000)	(1,000)
Options outstanding Ending Balance	150,000	281,000	201,000
Weighted Average Exercise Price
Options outstanding Beginning Balance	$ 8.79	$ 3.60
Options granted	$ 10.28	$ 12.97
Options exercised	$ 4.00	$ 2.84
Options forfeited	$ 10.28	$ 2.80
Options outstanding Ending Balance	$ 12.97	$ 8.79	$ 3.60
Intrinsic value of options exercised	1,000,000	800,000
Number Outstanding as of December 31, 2014
Number Outstanding as of December 31, 2014	150,000
Weighted Average Remaining Contractual Life (in Years)	3 years 8 months 23 days
Weighed Average Exercise Price (usd per share)	$ 12.97
Number Exercisable as of December 31, 2014	38,000
Weighted Average Remaining Contractual Life (in Years)	3 years 8 months 23 days
Weighted Average Exercise Price (usd per share)	$ 12.97
Intrinsic value of stock options outstanding	800,000
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Exercise Price	$ 18.21
Weighted Average Grant Date Fair Value (per share)
Shares of restricted stock repurchased to satisfy tax withholding obligations	383,811	186,778	211,000
Aggregate intrinsic value of restricted shares	23,000,000
Total unrecognized compensation cost related to non-vested restricted shares	8,800,000
Compensation expense related to restricted shares	4,900,000	6,000,000	6,300,000
Weighted Average Expected Option Phantom
Tax benefit attributable to all recorded stock-based compensation	2,600,000	3,000,000	2,300,000
Excess tax benefits from stock-based awards	1,260,000	305,000	(386,000)
$12.97
Number Outstanding as of December 31, 2014
Number Outstanding as of December 31, 2014	150,000
Weighted Average Remaining Contractual Life (in Years)	3 years 8 months 23 days
Weighed Average Exercise Price (usd per share)	$ 12.97
Stock Options And Employee Stock Purchase Plan
Weighted Average Grant Date Fair Value (per share)
Granted (usd per share)	$ 2.63	$ 2.24	$ 1.70
Fair value of equity instrument other than options	102,000	67,000	86,000
Weighted Average Expected Option Phantom
Compensation expense related to options and ESPP rights	104,000	84,000	66,000
Cash received from exercise of options and ESPP	900,000	500,000	300,000
Shares under the Employee Stock Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance								300,000
Shares available for future grants	92,436
Weighted Average Grant Date Fair Value (per share)
Employee Stock Purchase Plan (ESPP), Intrinsic Value of Purchased Shares	67,000
Total unrecognized compensation cost, weighted-average recognition period	1 year
Percentage of compensation that participating employees can contribute to purchase common stock, minimum								1.00%
Percentage of compensation that participating employees can contribute to purchase common stock, maximum								15.00%
Common shares that participating employees can purchase in any plan year, shares								1,000
Percentage of discount from fair market value that eligible employees can purchase common stock								15.00%
Common shares that participating employees can purchase in any plan year, amount								25,000
Shares issued under the ESPP	37,996.000	39,218.000		20,356	17,640	19,048	20,170
Shares issued under ESPP, weighted average price (usd per share)				$ 10.31	$ 10.26	$ 8.15	$ 7.11
Weighted Average Expected Option Phantom
Expected term	6 months	6 months	6 months
Risk-free rate, minimum	0.05%	0.08%	0.14%
Risk-free rate, maximum	0.06%	0.11%	0.15%
Expected volatility, minimum	25.20%	19.90%	8.30%
Expected volatility, maximum	29.30%	20.30%	29.40%
Dividend Yield	0.00%	0.00%	0.00%
Intrinsic value of ESPP	59,000
Unrecognized compensation cost related to non-vested stock options	9,000
Stock Incentive Plan 1999
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance								3,190,737
Shares under the 2009 Stock Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares of common stock reserved for issuance								1,000,000	2,700,000
Shares available for future grants	3,307,686
Shares under the 2009 Stock Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, terms								10 years
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	200,000	100,000	0
Weighted Average Expected Option Phantom
Expected term	3 years 9 months	3 years 9 months
Risk-free rate, minimum	1.40%	1.40%
Risk-free rate, maximum	1.70%	1.60%
Expected volatility, minimum	36.70%	37.00%
Expected volatility, maximum	37.10%	37.10%
Dividend Yield	0.00%	0.00%
Stock options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards, vesting period								4 years
Performance based restricted stock | President
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation expense	600,000
Unrecognized Tax Benefits, Period Increase (Decrease)	0
Restricted Stock
Granted (shares)	31,250
Weighted Average Grant Date Fair Value (per share)
Granted (usd per share)	$ 12.03
Restricted stock
Restricted Stock
Unvested, Beginning Balance (shares)	2,310,000	1,539,000
Granted (shares)	412,000	1,620,000
Vested (shares)	(931,000)	(471,000)
Forfeited (shares)	(526,000)	(378,000)
Unvested, Ending Balance (shares)	1,265,000	2,310,000	1,539,000
Weighted Average Grant Date Fair Value (per share)
Unvested, Beginning Balance (usd per share)	$ 10.01	$ 9.38
Granted (usd per share)	$ 11.73	$ 10.21	$ 9.19
Vested (usd per share)	$ 9.67	$ 8.93
Forfeited (usd per share)	$ 9.97	$ 9.62
Unvested, Ending Balance (usd per share)	$ 10.84	$ 10.01	$ 9.38
Fair value of equity instrument other than options	$ 9,000,000	$ 4,800,000	$ 5,100,000
Total unrecognized compensation cost, weighted-average recognition period	2 years 5 months 19 days
Restricted stock | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards, vesting period								4 years
Restricted stock | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock awards, vesting period								1 year