Term Loan (Details) (USD $)	1 Months Ended	3 Months Ended
	Jan. 31, 2013	Mar. 31, 2013
Term Loan
Term loan		$ 70,000,000
Senior unsecured term loan
Term Loan
Term loan	70,000,000
Line of credit facility, variable reference rate	one month LIBOR
Variable interest rate, basis points spread over variable reference rate (as a percent)	1.20%
Maximum interest rate (as a percent)	2.15%
Deferred financing costs incurred		$ 273,000