Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended		3 Months Ended									12 Months Ended			3 Months Ended
	Dec. 31, 2011 M	Dec. 31, 2010	Sep. 30, 2011 Marriott W	Jun. 30, 2011 Marriott W	Mar. 31, 2011 Marriott W	Sep. 30, 2010 Marriott W	Jun. 30, 2010 Marriott W	Mar. 31, 2010 Marriott W	Sep. 30, 2009 Marriott W	Jun. 30, 2009 Marriott W	Mar. 31, 2009 Marriott W	Dec. 31, 2011 Marriott D	Dec. 31, 2010 Marriott D	Dec. 31, 2009 Marriott D	Dec. 31, 2011 Marriott Maximum W	Dec. 31, 2010 Marriott Maximum W	Dec. 31, 2009 Marriott Maximum W	Dec. 31, 2011 Marriott Minimum W	Dec. 31, 2010 Marriott Minimum W	Dec. 31, 2009 Marriott Minimum W
Reporting Periods
Weeks reported in quarter			12	12	12	12	12	12	12	12	12
Weeks reported in fourth quarter															17	17	17	16	16	16
Number of days excluded from fiscal period												1	1	1
Estimated reduction in revenue amount recorded due to one less day included in fiscal period												$ 1,100,000	$ 500,000	$ 200,000
Estimated reduction in net income amount recorded due to one less day included in fiscal period												300,000	100,000	41,000
Cash and Cash Equivalents
Original maturity period of short-term investments to be considered as cash equivalents (in months)	3
Accounts Receivable
Allowance for doubtful accounts	$ 200,000	$ 100,000