Subsequent Events (Details) (USD $) In Millions, unless otherwise specified		0 Months Ended					0 Months Ended
	Apr. 25, 2011 Revolving credit facility	Jul. 05, 2013 Subsequent event Term Loan	Jul. 05, 2013 Subsequent event Term Loan Maximum	Jul. 05, 2013 Subsequent event Term Loan Prior to July 5, 2014	Jul. 05, 2013 Subsequent event Term Loan Between July 5, 2014 and July 5, 2015	Jul. 05, 2013 Subsequent event Term Loan Between July 5, 2015 and July 5, 2016	Jul. 05, 2013 Subsequent event Revolving credit facility item
Subsequent events
Term		3 years
Amount of loan		$ 15.0
Interest rate per annum (as a percent)		5.50%
Amortization schedule		10 years
Net operating income multiplier used to calculate debt service ratio		4
Period over which specified quarterly net operating income required to be maintained in excess of actual annual debt service		12 months
Actual annual debt service multiplier used to calculate debt service ratio		1.45
Minimum consolidated domestic cash and cash equivalents, and investments with maturities of fewer than twelve (12) months required to maintain		7.5
Percentage increase over applicable interest rate, upon an event of default		5.00%
Prepayments as percentage of outstanding balance			20.00%
Early termination fee on amounts prepaid (as a percent)				3.00%	2.00%	1.00%
Maximum borrowing capacity under the credit facility	30.0						30.0
Number of letters of credit cash collateralized							2
Amount of letters of credit cash collateralized							1.5
Early termination fee							$ 0.3