Stock- Based Compensation (Details 2) (USD $)	Dec. 31, 2011 Y	Dec. 31, 2010
Segregated disclosure of options outstanding
Options outstanding	1,737,881	1,779,184
Weighted average exercise price, Outstanding	$ 13.95	$ 12.21
Remaining contractual life	6.5
Options exercisable	949,966
Weighted average exercise price, exercisable	$ 12.81
Less Than or Equal to $12.52 [Member]
Segregated disclosure of options outstanding
Options outstanding	681,000
Weighted average exercise price, Outstanding	$ 4.82
Remaining contractual life	7.3
Options exercisable	391,000
Weighted average exercise price, exercisable	$ 4.82
Greater than $12.52 and less than $19.33 [Member]
Segregated disclosure of options outstanding
Options outstanding	479,169
Weighted average exercise price, Outstanding	$ 17.17
Remaining contractual life	5.8
Options exercisable	291,424
Weighted average exercise price, exercisable	$ 16.18
Greater than or equal to $19.33 [Member]
Segregated disclosure of options outstanding
Options outstanding	577,712
Weighted average exercise price, Outstanding	$ 22.05
Remaining contractual life	6.1
Options exercisable	267,542
Weighted average exercise price, exercisable	$ 20.82