Stock-Based Compensation Stock Based Compensation (Narrative) (Details) (USD $)			12 Months Ended													12 Months Ended						12 Months Ended					12 Months Ended						12 Months Ended				12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Stock Options [Member]	Dec. 31, 2011 Stock Options [Member]	Dec. 31, 2010 Stock Options [Member]	Dec. 31, 2012 Time-Vested Deferred Stock [Member]	Dec. 31, 2011 Time-Vested Deferred Stock [Member]	Dec. 31, 2010 Time-Vested Deferred Stock [Member]	Dec. 31, 2012 Stock Appreciation Rights [Member]	Dec. 31, 2011 Stock Appreciation Rights [Member]	Dec. 31, 2010 Stock Appreciation Rights [Member]	Dec. 31, 2012 Employee Stock [Member]	Dec. 31, 2011 Employee Stock [Member]	Dec. 31, 2010 Employee Stock [Member]	Dec. 31, 2012 Amended and Restated 2004 Omnibus Stock Plan	Dec. 31, 2012 Amended and Restated 2004 Omnibus Stock Plan Stock Options [Member]	Dec. 31, 2010 Amended and Restated 2004 Omnibus Stock Plan Stock Options [Member]	Dec. 31, 2012 Amended and Restated 2004 Omnibus Stock Plan Time-Vested Deferred Stock [Member]	Dec. 31, 2011 Amended and Restated 2004 Omnibus Stock Plan Time-Vested Deferred Stock [Member]	Dec. 31, 2010 Amended and Restated 2004 Omnibus Stock Plan Time-Vested Deferred Stock [Member]	Dec. 31, 2009 Amended and Restated 2004 Omnibus Stock Plan Time-Vested Deferred Stock [Member]	Dec. 31, 2012 Amended and Restated 2004 Omnibus Stock Plan Time-Vested Deferred Stock [Member] Minimum [Member]	Dec. 31, 2012 Amended and Restated 2004 Omnibus Stock Plan Time-Vested Deferred Stock [Member] Maximum [Member]	Dec. 31, 2012 Amended and Restated 2004 Omnibus Stock Plan Stock Appreciation Rights [Member]	Dec. 31, 2011 Amended and Restated 2004 Omnibus Stock Plan Stock Appreciation Rights [Member]	Dec. 31, 2010 Amended and Restated 2004 Omnibus Stock Plan Stock Appreciation Rights [Member]	Dec. 31, 2012 Amended and Restated 2004 Omnibus Stock Plan Stock Appreciation Rights [Member] Minimum [Member]	Dec. 31, 2012 Amended and Restated 2004 Omnibus Stock Plan Stock Appreciation Rights [Member] Maximum [Member]	Dec. 31, 2012 Amended and Restated 2004 Omnibus Stock Plan Performance Contingent Deferred Stock	Dec. 31, 2011 Amended and Restated 2004 Omnibus Stock Plan Performance Contingent Deferred Stock	Dec. 31, 2010 Amended and Restated 2004 Omnibus Stock Plan Performance Contingent Deferred Stock	Dec. 31, 2009 Amended and Restated 2004 Omnibus Stock Plan Performance Contingent Deferred Stock	Dec. 31, 2012 Amended and Restated 2004 Omnibus Stock Plan Performance Contingent Deferred Stock Minimum [Member]	Dec. 31, 2012 Amended and Restated 2004 Omnibus Stock Plan Performance Contingent Deferred Stock Maximum [Member]	Dec. 31, 2012 Stock Purchase Plan [Member]	Dec. 31, 2012 Stock Purchase Plan [Member] Employee Stock [Member]	Dec. 31, 2012 Stock Purchase Plan [Member] Employee Stock [Member] Minimum [Member]	Dec. 31, 2012 Stock Purchase Plan [Member] Employee Stock [Member] Maximum [Member]	Dec. 31, 2012 Director [Member] Amended and Restated 2004 Omnibus Stock Plan Time-Vested Deferred Stock [Member]	Dec. 31, 2012 Operating and Administrative Expenses [Member]	Dec. 31, 2011 Operating and Administrative Expenses [Member]	Dec. 31, 2010 Operating and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized	100,000,000	100,000,000													2,300,000
Total stock-based compensation expense			$ 90,000	$ 0	$ 0	$ 1,920,000	$ 1,625,000	$ 1,751,000	$ 647,000	$ 850,000	$ 988,000	$ 126,000	$ 162,000	$ 240,000																										$ 3,414,000	$ 3,358,000	$ 2,979,000
Total stock-based compensation expense, net																																								2,100,000	2,100,000	1,800,000
Defined Contribution Plan, Employer Matching Contribution on Equity Units, Percent																																			33.33%
Vesting period (in years)																5 years						2 years	5 years				3 years	5 years					2 years	5 years			3 years	10 years	5 years
Total unrecognized compensation costs related to non-vested options awards																800,000
Remaining weighted average unrecognized compensation cost related to non-vested awards (in years)																4 years 2 months 12 days		2 years 10 months 19 days						3 years 1 month 6 days					4 years
Expiration period																								7 years
Intrinsic value																								500,000	100,000	100,000
Unrecognized compensation costs for share based awards other than options																		3,000,000						1,200,000					1,200,000
Units available under plan (in units)																		400,000	416,000	218,000	182,000								107,000	107,000	0	0				56,000
Weighted average market price of shares accumulated under plan (in dollars per share)																		$ 15.82	$ 14.68	$ 16.57	$ 18.50								$ 15.78	$ 13.67	$ 0.00	$ 0.00				$ 13.79
Intrinsic value of options exercised																	$ 100,000