Employee Benefit Plans (Matching Retirement/Savings Plan) (Details) (USD $)	12 Months Ended			6 Months Ended	12 Months Ended				6 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Jun. 30, 2012 Granite Corp. [Member]	Dec. 31, 2012 Granite Corp. [Member] balance	Dec. 31, 2013 COB Matching Retirement/Savings Plan [Member]	Dec. 31, 2012 COB Matching Retirement/Savings Plan [Member]	Dec. 31, 2011 COB Matching Retirement/Savings Plan [Member]	Jun. 30, 2012 Tax-Qualified Profit-Sharing and Savings Retirement Plan [Member] Granite Corp. [Member]	Dec. 31, 2013 Tax-Qualified Profit-Sharing and Savings Retirement Plan [Member] Granite Corp. [Member]	Dec. 31, 2012 Tax-Qualified Profit-Sharing and Savings Retirement Plan [Member] Granite Corp. [Member]	Dec. 31, 2013 Non-Tax Qualified Profit-Sharing Supplemental Executive Retirement Plan [Member] Granite Corp. [Member]	Dec. 31, 2012 Non-Tax Qualified Profit-Sharing Supplemental Executive Retirement Plan [Member] Granite Corp. [Member]
Defined Contribution Pension and Other Postretirement Plans Disclosure [Line Items]
Employer matching contribution percentage	50.00%			50.00%		50.00%			50.00%
Percentage of pay deferred by employee eligible for employer matching contributions	6.00%			6.00%		6.00%			6.00%
Discretionary contributions						$ 0	$ 0	$ 0
Matching and discretionary contributions	$ 500,000	$ 600,000	$ 400,000			$ 500,000	$ 600,000	$ 400,000		$ 0	$ 0	$ 0	$ 0
Non-tax qualified profit-sharing supplemental executive retirement plan, remaining balances paid					2