Investments (Schedule Of Available-For-Sale Securities Investments Results)(Details) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale equity securities, amoritzed cost	$ 7,900,000	$ 7,900,000
Available-for-sales securities, gross unrealized gains	20,980,000	16,860,000
Available-for-sale securities, gross unrealized losses	70,000	0
Available-for-sale securities gross, Fair Value	28,810,000	24,760,000
Available-for-sale Securities, Gross Unrealized Gain (Loss)	20,910,000	16,860,000
Deferred taxes on unrealized holdings gains	8,364,000	6,744,000
Unrealized gains recorded in equity, net of deferred tax	12,546,000	10,116,000
Cement Industry [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale equity securities, amoritzed cost	2,940,000	2,940,000
Available-for-sales securities, gross unrealized gains	13,710,000	9,730,000
Available-for-sale securities, gross unrealized losses	0	0
Available-for-sale securities gross, Fair Value	16,650,000	12,670,000
General Building 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	3,050,000	2,970,000
Available-for-sale securities, gross unrealized losses	0	0
Available-for-sale securities gross, Fair Value	6,650,000	6,570,000
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	340,000
Available-for-sales securities, gross unrealized gains	4,220,000	4,090,000
Available-for-sale securities, gross unrealized losses	0	0
Available-for-sale securities gross, Fair Value	4,560,000	4,430,000
Residential Construction Industry [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale equity securities, amoritzed cost	1,020,000	1,020,000
Available-for-sales securities, gross unrealized gains	0	70,000
Available-for-sale securities, gross unrealized losses	70,000	0
Available-for-sale securities gross, Fair Value	$ 950,000	$ 1,090,000