Summary Of Significant Accounting Policies (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended			3 Months Ended								9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2014 Minimum [Member]	Sep. 30, 2014 Maximum [Member]	Sep. 30, 2014 Stock Appreciation Rights (SARs) [Member]	Sep. 30, 2014 Stock Appreciation Rights (SARs) [Member] Minimum [Member]	Sep. 30, 2014 Stock Appreciation Rights (SARs) [Member] Maximum [Member]	Sep. 30, 2014 Restricted Stock Awards And Units [Member] Minimum [Member]	Sep. 30, 2014 Restricted Stock Awards And Units [Member] Maximum [Member]	Sep. 30, 2014 Restricted Stock Units (RSUs) [Member] Contractor [Member]	Sep. 30, 2014 Performance Shares [Member] Minimum [Member] Rate	Sep. 30, 2014 Performance Shares [Member] Maximum [Member] Rate	Feb. 22, 2013 Carrizo United Kingdom [Member]
Summary Of Significant Accounting Policies [Line Items]
Outstanding checks included in accounts payable	$ 47.5		$ 47.5		$ 2.2
Percentage of non-operating working interest and overriding royalty interests																15.00%
Discontinued Operations, Sale Price																184.0
Accounts Receivable, Related Parties, Current	0.1		0.1		6.6
Accounts Payable, Related Parties, Current	1.3		1.3		2.8
Internal costs capitalized, Oil and Gas Producing Activities	3.4	3.8	14.1	10.1
Average Depreciation Depletion And Amortization Per Boe	26.75	19.75	26.58	19.34
Oil and Gas, Exploratory Period	5 years
Capitalized interest	$ 8.7	$ 7.5	$ 25.0	$ 21.8
Reserves discount factor	10.00%
Estimated useful life, years						5 years	10 years
Current Long-Term Derivative Instrument Strategy			36 months
Vesting period, in years			3 years					3 years			1 year	3 years	3 years
Shared Based Compensation Arrangement By Share Based Payment Award, Award Vesting Rights Percentage Range														0.00%	200.00%
Expiration period after date of grant, in years									4 years	7 years