Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended				3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		0 Months Ended	3 Months Ended		6 Months Ended	1 Months Ended		3 Months Ended	6 Months Ended		3 Months Ended		6 Months Ended						6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jan. 31, 2014	Jun. 30, 2013	Jan. 31, 2013	Jun. 30, 2014 $10.28	Jun. 30, 2014 $10.28	Jun. 30, 2014 $12.97	Jun. 30, 2014 $12.97	Jun. 30, 2014 Stock Options	Jun. 30, 2013 Stock Options	Jun. 30, 2014 Stock Options	Jun. 30, 2013 Stock Options	Jun. 30, 2014 Restricted Stock	Jun. 30, 2013 Restricted Stock	Jun. 30, 2014 Restricted Stock	Jun. 30, 2013 Restricted Stock	Mar. 31, 2014 Performance-based Restricted Stock	Jun. 30, 2014 Performance-based Restricted Stock	Jun. 30, 2013 Performance-based Restricted Stock	Jun. 30, 2014 Performance-based Restricted Stock	Apr. 30, 2014 Performance-based Restricted Stock Two Executives	Mar. 31, 2014 Performance-based Restricted Stock Two Executives	Jun. 30, 2014 Performance-based Restricted Stock Two Executives	Jun. 30, 2014 Performance-based Restricted Stock Two Executives executive grant	Jun. 30, 2013 Performance-based Restricted Stock Two Executives	Jun. 30, 2014 Options and ESPP	Jun. 30, 2013 Options and ESPP	Jun. 30, 2014 Options and ESPP	Jun. 30, 2013 Options and ESPP	Jun. 30, 2014 ESPP	Jun. 30, 2013 ESPP	Jan. 31, 2014 ESPP	Jan. 31, 2013 ESPP	Jun. 30, 2014 ESPP Employee Stock Purchase Plan 2009
Shares
Options outstanding at December 31, 2013 (in shares)			281,000
Options granted (in shares)			100,000		0
Options exercised (in shares)			(131,000)
Options forfeited (in shares)			0
Options outstanding at March 31, 2014 (in shares)	250,000		250,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares			0		0
Weighted Average Exercise Price
Options outstanding at December 31, 2013 (usd per share)			$ 8.79
Options granted (usd per share)			$ 10.28
Options exercised (usd per share)			$ 4.00
Options forfeited (usd per share)			$ 0.00
Options outstanding at March 31, 2014 (usd per share)	$ 11.89		$ 11.89
Intrinsic value of options exercised	$ 900,000	$ 509,000	$ 949,300		$ 579,000
Lower Range of Exercise Price							$ 10.28		$ 12.97
Upper Range of Exercise Price								$ 10.28		$ 12.97
Number Outstanding as of June 30, 2014
Options Outstanding, Number of Outstanding as of March 31, 2014 (shares)	250,000		250,000				100,000	100,000	150,000	150,000
Options Outstanding, Weighted Average Remaining Contractual Life (in years)			4 years 5 months 12 days					4 years 9 months 7 days		4 years 2 months 22 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 11.89		$ 11.89				$ 10.28	$ 10.28	$ 12.97	$ 12.97
Options Exercisable, Number of Outstanding as of March 31, 2014 (shares)	0		0				0	0	0	0
Options Exercisable, Weighted Average Remaining Contractual Life (in years)			0 days					0 days		0 days
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 0.00		$ 0.00				$ 0.00	$ 0.00	$ 0.00	$ 0.00
Intrinsic value of stock options outstanding	200,000		200,000
Restricted Stock
Unvested as of December 31, 2013 (in shares)																	2,310,000
Granted (shares)																	311,000				0		62,500	31,250			0
Vested (shares)																	(811,000)
Forfeited (shares)																	(287,000)
Unvested as of March 31, 2014 (in shares)															1,523,000		1,523,000
Weighted Average Grant Date Fair Value
Unvested, Beginning Balance (usd per share)																	$ 10.01
Granted (usd per share)																	$ 11.49	$ 9.34					$ 10.28	$ 12.03						$ 1.98	$ 2.82
Vested (usd per share)																	$ 9.44
Forfeited (usd per share)																	$ 9.97
Unvested, Ending Balance (usd per share)															$ 10.63		$ 10.63
Fair value of equity instrument other than options																	7,700,000	4,000,000							400,000	400,000				44,000	29,000
Shares of restricted stock repurchased to satisfy tax withholding obligations																	337,484	176,689
Aggregate intrinsic value of restricted shares															18,600,000		18,600,000								0	0
Total unrecognized compensation cost related to non-vested restricted shares															12,200,000		12,200,000			2,100,000		2,100,000			0	0
Total unrecognized compensation cost, weighted-average recognition period																	2 years 8 months 22 days					2 years 9 months 1 day														1 month
Stock-based compensation expense	1,810,000	1,583,000	2,998,000		2,887,000						59,000	0	106,000	0	1,300,000	1,600,000	2,500,000	2,900,000		200,000		200,000				0		29,000	20,000	49,000	38,000
Percentage of bonus paid in restricted stock																			75.00%
Percentage of bonus paid in cash																			25.00%
Vesting period																			3 years
Number of executives granted awards																										2
Number of grants																										2
Shares issued under the ESPP				17,640		20,170
ESPP, purchase price (usd per share)																																		$ 10.26	$ 7.11
Employee Stock Purchase Program Valuation Assumptions
Expected term													36 months 275 days																			6 months	6 months
Risk-free rate													1.68%																			0.06%	0.11%
Expected volatility													36.69%																			29.30%	19.90%
Dividend yield													0.00%																			0.00%	0.00%
Intrinsic value of rights outstanding ESPP																																				36,000
Compensation costs not yet recognized																																				9,000
Cash received from exercise of options and ESPP																														$ 700,000	$ 300,000