Equity-Based Compensation (Stock Compensation Plans) (Narrative) (Details) (USD $)		12 Months Ended					12 Months Ended			12 Months Ended
	Dec. 31, 2011 WhereNet options [Member]	Dec. 31, 2011 Restricted Stock Awards [Member]	Dec. 31, 2011 Stock Option And Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2010 Stock Option And Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2009 Stock Option And Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2008 Stock Option And Stock Appreciation Rights (SARs) [Member]	Dec. 31, 2011 2011 Plan [Member] days years	Dec. 31, 2011 2006 Plan [Member] days years	Dec. 31, 2011 1997 Plan [Member]	Dec. 31, 2011 2002 Director Plan [Member] years	Dec. 31, 2011 2001 Stock Purchase Plan [Member] hours	Dec. 31, 2010 2001 Stock Purchase Plan [Member]	Dec. 31, 2009 2001 Stock Purchase Plan [Member]	Dec. 31, 2011 Date Of The Grant [Member] Prior To April 1, 2009 [Member] 2001 Stock Purchase Plan [Member]	Dec. 31, 2011 Date Of The Grant [Member] Effective April 1, 2009 [Member] 2001 Stock Purchase Plan [Member]	Dec. 31, 2011 Date Of Purchase [Member] Prior To April 1, 2009 [Member] 2001 Stock Purchase Plan [Member]	Dec. 31, 2011 Date Of Purchase [Member] Effective April 1, 2009 [Member] 2001 Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance of awards							5,500,000
Shares available for grant							5,455,022
Options outstanding			2,990,374	3,575,746	3,451,945	3,139,174	32,341
Minimum vesting period, years		three	four
Maximum vesting period, years		five	five
Expiration period (in years)							10	10		10
Expiration period, if employee is terminated involuntarily other than for cause (days)							90	90
Expiration period, if employee voluntarily terminates his or her employment (days)							30	30
Expiration period, if employee's employment terminates due to death, disability, or retirement (Years)							1	1
Shares outstanding and exercisable	15,584		1,894,324	2,042,664	1,884,449			2,040,232	822,217	80,000
Minimum working hours per week											20
Maximum percentage of compensation deductions											10.00%
Percentage of purchase price on fair market value														85.00%	95.00%	85.00%	95.00%
Stock purchase plan expense											$ 321,000	$ 315,000	$ 514,000