Subsequent Events (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2014 Rate
Subsequent Event [Line Items]
Percentage of cumulative consolidated net income after June 30, 2014 plus $353.9 million	50.00%
Percentage of net proceeds of any equity offerings after June 30, 2014 plus $353.9 million minimum tangible net worth	50.00%
First Amendment to New Unsecured Credit Facility [Member]
Subsequent Event [Line Items]
Minimum Tangible Net Worth	$ 353.9
Line of Credit Facility, Current Borrowing Capacity	300
Line of Credit Facility, Maximum Borrowing Capacity	400
Sub-limit for letters of credit	125
First Amendment to New Unsecured Credit Facility [Member] | Maximum [Member]
Subsequent Event [Line Items]
Credit Facility, Basis Spread on Variable Rate	2.50%
First Amendment to New Unsecured Credit Facility [Member] | Minimum [Member]
Subsequent Event [Line Items]
Credit Facility, Basis Spread on Variable Rate	1.50%
New Unsecured Credit Facility [Member]
Subsequent Event [Line Items]
Line of Credit Facility, Current Borrowing Capacity	200
Line of Credit Facility, Maximum Borrowing Capacity	225
Sub-limit for letters of credit	$ 100
New Unsecured Credit Facility [Member] | Maximum [Member]
Subsequent Event [Line Items]
Credit Facility, Basis Spread on Variable Rate	3.25%
New Unsecured Credit Facility [Member] | Minimum [Member]
Subsequent Event [Line Items]
Credit Facility, Basis Spread on Variable Rate	2.25%