Share Based Payments (Narrative) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense		$ 6,523,000	$ 6,028,000	$ 9,746,000
Restricted Shares Forfeiture (in shares)			1,948,324
Annual Long Term Equity Incentive Programs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense		4,490,000	$ 4,083,000	4,858,000
Unearned Compensation		$ 2,484,000	3,541,000
2015 Multi-Year Long Term Equity Incentive Program (“2015 Multi-Year EIP”) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Terms of Share-based payment awards		On March 18, 2015, the Compensation Committee approved the 2015 Multi-Year Long Term Equity Incentive Program ("2015 Multi-Year EIP"). The shares or LTIP Units issuable under this program are based on the Company's achievement of a certain level of (1) absolute total shareholder return (37.50% of the award), (2) relative total shareholder return as compared to the Company's peer group (37.50% of the award), and (3) relative growth in revenue per available room compared to the Company's peer group (25% of the award). This program has a three-year performance period which commenced on January 1, 2015 and ends December 31, 2017. As of December 31, 2015, no shares or LTIP Units have been issued to the executive officers in settlement of 2015 Multi-Year EIP awards.
2014 Multi-Year Long Term Equity Incentive Program (“2014 Multi-Year EIP”) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Terms of Share-based payment awards		On April 11, 2014, the Compensation Committee approved the 2014 Multi-Year Long Term Equity Incentive Program ("2014 Multi-Year EIP"). The common shares issuable under this program are based on the Company's achievement of a certain level of (1) absolute total shareholder return (37.50% of the award), (2) relative total shareholder return as compared to the Company's peer group (37.50% of the award), and (3) relative growth in revenue per available room compared to the Company's peer group (25% of the award). This program has a three-year performance period which commenced on January 1, 2014 and ends December 31, 2016. As of December 31, 2015 no common shares have been issued to the executive officers in settlement of 2014 Multi-Year EIP awards.
2013 Multi-Year Long Term Equity Incentive Program (“2013 Multi-Year EIP”) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Terms of Share-based payment awards		On April 15, 2013, the Compensation Committee approved the 2013 Multi-Year Long Term Equity Incentive Program ("2013 Multi-Year EIP"). The common shares issuable under this program are based on the Company's achievement of a certain level of (1) absolute total shareholder return (50% of the award), (2) relative total shareholder return as compared to the Company's peer group (25% of the award), and (3) relative growth in revenue per available room compared to the Company's peer group (25% of the award). This program has a three year performance period which commenced on January 1, 2013 and ends December 31, 2015. As of December 31, 2015 no common shares have been issued to the executive officers in settlement of 2013 Multi-Year EIP awards.
Multi-Year LTIP [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense		$ 818,000	598,000	3,481,000
Unearned Compensation		1,548,000	1,621,000
Multi-Year LTIP Trustee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense		59,000	71,000	55,000
Unearned Compensation		$ 67,000	$ 127,000
Shares Vested (in shares)		6,005	3,502
Annual Retainer [Member] | Multi-Year LTIP Trustee [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense		$ 93,000	$ 220,000	160,000
Percentage premium on retainer equity option (in hundredths)		25.00%
LTIP Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unearned Compensation		$ 2,484,000	$ 3,541,000
Shares Issued (in shares)		569,105
Shares Vested (in shares)		429,467	76,688
Restricted Common Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense		$ 455,000	$ 399,000	522,000
Restricted Share Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unearned Compensation		$ 491,000	$ 322,000
Shares Issued (in shares)		67,423
Shares Vested (in shares)		37,794	23,203
Board Of Trustees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense		$ 434,000	$ 457,000	496,000
Shares Issued (in shares)	10,442	7,500
Share Price on date of grant (in dollars per share)	$ 25.92	$ 21.76
Non-employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock based compensation expense		$ 174,000	200,000	$ 174,000
Unearned Compensation		$ 90,000	$ 81,000
Shares Issued (in shares)		14,657
Shares Vested (in shares)		10,981,000	3,750,000