Stock Based Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility (in hundredths)		71.84%
Expected term		4 years 9 months	4 years 9 months
Risk-free interest rate (in hundredths)		0.66%
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility (in hundredths)	44.17%		68.91%
Expected term	1 year 3 months
Risk-free interest rate (in hundredths)	0.12%		1.02%
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility (in hundredths)	71.58%		71.53%
Expected term	4 years 9 months
Risk-free interest rate (in hundredths)	1.37%		2.00%
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average fair value per share (in dollars per share)	$ 7.97	$ 7.14	$ 3.18
Number of Shares [Roll Forward]
Outstanding, beginning balance (in shares)	2,264,399
Granted (in shares)	530,835
Exercised (in shares)	(536,565)
Forfeited or expired (in shares)	(28,700)
Outstanding, ending balance (in shares)	2,229,969	2,264,399
Options exercisable (in shares)	1,149,069	1,234,623
Weighted Average Exercise Price [Roll Forward]
Outstanding, beginning balance (in dollars per share)	$ 7.02
Granted (in dollars per share)	$ 16.06
Exercised (in dollars per share)	$ 6.01
Forfeited or expired (in dollars per share)	$ 8.99
Outstanding, ending balance (in dollars per share)	$ 9.39	$ 7.02
Exercisable, ending balance (in dollars per share)	$ 6.88
Aggregate intrinsic value exercised	$ 5,017	$ 1,658	$ 70
Aggregate intrinsic value outstanding	18,827
Aggregate intrinsic value exercisable	12,585
Stock Options [Member] | Selling, General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option expense	1,994	1,303	1,028
Stock Options [Member] | Unvested [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation cost related to unvested share-based awards not yet recognized	6,436
Weighted average vesting period	2 years 9 months 18 days
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	6 months
Nonvested Restricted Stock Number of Shares [Roll Forward]
Nonvested, beginning balance (in shares)	31,145
Granted (in shares)	31,648
Vested during period (in shares)	(62,793)
Forfeited (in shares)	0
Nonvested, ending balance (in shares)	0
Nonvested Restricted Stock, Weighted-Average Grant-Date Fair Value [Roll Forward]
Nonvested, beginning balance (in dollars per share)	$ 5.76
Granted (in dollars per share)	$ 12.64
Vested during period (in dollars per share)	$ 9.23
Forfeited (in dollars per share)	$ 0
Nonvested, ending balance (in dollars per share)	$ 0
Restricted Stock [Member] | Selling, General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock expense	427	446	497
Nonvested Stock Option [Member]
Nonvested Stock Options, Number of Shares [Roll Forward]
Nonvested, beginning balance (in shares)	1,029,776
Granted (in shares)	530,835
Vested during period (in shares)	(455,211)
Forfeited (in shares)	(24,500)
Nonvested, ending balance (in shares)	1,080,900
Nonvested Stock Options, Weighted-Average Grant-Date Fair Value [Roll Forward]
Nonvested, beginning balance (in dollars per share)	$ 4.62
Granted (in dollars per share)	$ 7.97
Vested during period (in dollars per share)	$ 4.05
Forfeited (in dollars per share)	$ 4.73
Nonvested, ending balance (in dollars per share)	$ 6.50
Performance shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	3 years
Performance shares [Member] | Selling, General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance share expense	404	53	40
Cash Settled Performance Share units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance period	3 years
Cash Settled Performance Share units [Member] | Selling, General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance share unit expense	$ 2,620	$ 1,529	$ 415