Employee Retirement Plans (Schedule Of Contributions Made By The Company To Each Multiemployer Plan) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions	$ 307	$ 401	$ 350
National Integrated Group Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions	186	197	187
Sheet Metal Workers' National Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions	50	41	38
Sheet Metal Workers' Pension Plan Of Northern California [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions	63	154	118
Western Metal Industry Pension Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Contributions	$ 8	$ 9	$ 7