Acquisitions (Narrative) (Details) (USD $)	12 Months Ended			3 Months Ended	12 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Kenny	Dec. 31, 2013 Kenny	Dec. 28, 2012 Kenny	Dec. 31, 2013 Notes Payable to Banks [Member]	Dec. 31, 2013 Trade Names [Member] Kenny	Dec. 31, 2013 Minimum [Member] Order or Production Backlog [Member] Kenny	Dec. 31, 2013 Minimum [Member] Customer Relationships [Member] Kenny	Dec. 31, 2013 Maximum [Member] Order or Production Backlog [Member] Kenny	Dec. 31, 2013 Maximum [Member] Customer Relationships [Member] Kenny
Business Acquisition [Line Items]
Percentage of outstanding shares of Kenny acquired						100.00%
Total purchase price					$ 141,114,000
Proceeds from borrowing under existing credit facility							70,000,000
Post-closing adjustments expected to be paid					8,400,000
Adjustment to preliminary values assigned to certain assets and liabilities					400,000
Estimated useful lives for acquired intangible assets								10 years	1 year	1 year	8 years	8 years
Goodwill	53,799,000	55,419,000			43,899,000
Gross amout due under contracts					88,725,000
Federal statutory tax rate, percent	35.00%	35.00%	35.00%		39.00%
Effective tax rate, percent	30.10%	26.10%	26.10%		36.00%
Business Combination, Integration Related Costs					3,100,000
Acquisition-related costs				4,400,000	4,400,000
Business Combination, Indemnification Assets, Amount as of Acquisition Date					$ 13,000,000