Stock-Based Compensation (Details 1) (USD $)	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Director [Member] | 2008 Equity Incentive Plan [Member]
Summary of nonvested stock awards granted
Vesting Period	1 year
Director [Member] | 2008 Equity Incentive Plan [Member] | Restricted Stock and Restricted Stock Units [Member]
Summary of nonvested stock awards granted
Vesting Period	1 year
Director [Member]
Summary of nonvested stock awards granted
Vesting Period		3 years
Weighted Average Grant Date Fair Value		$ 3.95
Director [Member] | 2008 Equity Incentive Plan [Member] | Restricted Stock and Restricted Stock Units [Member]
Summary of nonvested stock awards granted
Grantee Type		Director
No. of Shares Granted		8,546
Vesting Period		3 years
Weighted Average Grant Date Fair Value		$ 6.11
Director group [Member]
Summary of nonvested stock awards granted
Vesting period		1 year or less
Vesting Period	1 year
Weighted Average Grant Date Fair Value	$ 3.97	$ 4.13
Director group [Member] | 2008 Equity Incentive Plan [Member] | Restricted Stock and Restricted Stock Units [Member]
Summary of nonvested stock awards granted
Grantee Type		Director group
No. of Shares Granted		58,110
Vesting period		1 year or less
Weighted Average Grant Date Fair Value		$ 7.31
Director group [Member] | 2008 Equity Incentive Plan [Member] | Restricted Stock and Restricted Stock Units [Member]
Summary of nonvested stock awards granted
Grantee Type	Director group
No. of Shares Granted	51,276
Vesting Period	1 year
Weighted Average Grant Date Fair Value	$ 7.53
Employee group [Member]
Summary of nonvested stock awards granted
Vesting Period		2 years
Weighted Average Grant Date Fair Value		$ 3.72
Employee group [Member] | 2008 Equity Incentive Plan [Member] | Restricted Stock and Restricted Stock Units [Member]
Summary of nonvested stock awards granted
Grantee Type		Employee group
No. of Shares Granted		60,000
Vesting Period		2 years
Weighted Average Grant Date Fair Value		$ 6.09
Employee group [Member]
Summary of nonvested stock awards granted
Vesting Period	3 years	3 years
Weighted Average Grant Date Fair Value	$ 4.11	$ 4.33
Employee group [Member] | 2008 Equity Incentive Plan [Member] | Restricted Stock and Restricted Stock Units [Member]
Summary of nonvested stock awards granted
Grantee Type	Employee group	Employee group
No. of Shares Granted	405,486	455,064
Vesting Period	3 years	3 years
Weighted Average Grant Date Fair Value	$ 7.53	$ 7.41