Management Agreement And Related Party Transactions (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011
1.50% [Member] | Maximum [Member]
Management Agreement And Related Party Transactions [Line Items]
Management fee as a fraction of percentage of net assets	1/12
Percentage of net assets	1.50%
Net Assets	$ 250,000,000
1.25% [Member]
Management Agreement And Related Party Transactions [Line Items]
Management fee as a fraction of percentage of net assets	1/12
Percentage of net assets	1.25%
1.25% [Member] | Minimum [Member]
Management Agreement And Related Party Transactions [Line Items]
Net Assets	250,000,000
1.25% [Member] | Maximum [Member]
Management Agreement And Related Party Transactions [Line Items]
Net Assets	500,000,000
1.00% [Member] | Minimum [Member]
Management Agreement And Related Party Transactions [Line Items]
Management fee as a fraction of percentage of net assets	1/12
Percentage of net assets	1.00%
Net Assets	$ 500,000,000