Investments (Schedule Of Available-For-Sale Securities Investments Results)(Details) (USD $)	Jun. 30, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale equity securities, amoritzed cost	$ 7,490,000	$ 8,260,000
Available-for-sales securities, gross unrealized gains	14,705,000	16,500,000
Available-for-sale securities, gross unrealized losses	55,000	0
Avaialbe-for-sale securities gross, Fair Value	22,140,000	24,760,000
Total gross unrealized gains, net of losses	14,650,000	16,500,000
Deferred taxes on unrealized holdings gains	5,860,000	6,600,000
Unrealized gains recorded in equity, net of deferred tax	8,790,000	9,900,000
Cement Industry [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale equity securities, amoritzed cost	2,940,000	4,190,000
Available-for-sales securities, gross unrealized gains	8,465,000	8,290,000
Available-for-sale securities, gross unrealized losses	0	0
Avaialbe-for-sale securities gross, Fair Value	11,405,000	12,480,000
General Buiding Materials Industry [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale equity securities, amoritzed cost	3,600,000	3,600,000
Available-for-sales securities, gross unrealized gains	1,750,000	2,150,000
Available-for-sale securities, gross unrealized losses	0	0
Avaialbe-for-sale securities gross, Fair Value	5,350,000	5,750,000
Oil And Gas Refining And Marketing Industry [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale equity securities, amoritzed cost	340,000	470,000
Available-for-sales securities, gross unrealized gains	4,490,000	6,060,000
Available-for-sale securities, gross unrealized losses	0	0
Avaialbe-for-sale securities gross, Fair Value	4,830,000	6,530,000
Residential Construction Industry [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale equity securities, amoritzed cost	610,000
Available-for-sales securities, gross unrealized gains	0
Available-for-sale securities, gross unrealized losses	55,000
Avaialbe-for-sale securities gross, Fair Value	$ 555,000

Available For Sale Securities Change In Net Unrealized Gain Loss Net Of Tax

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Available For Sale Securities Gross Fair Value

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This item represents the cost of equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments for other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

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Amount of deferred tax liability attributable to taxable temporary differences from unrealized gains on trading securities.

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