Term Loan (Details) (USD $)	0 Months Ended	1 Months Ended	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2013	Dec. 31, 2013	Jun. 30, 2014
Debt instrument
Term loan			$ 70,000,000	$ 70,000,000
Senior unsecured term loan
Debt instrument
Term loan	70,000,000	70,000,000
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			303,000
Deferred finance costs			$ 248,000	$ 217,000