Shareholders' Equity (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Changes in shareholders' equity that are attributable to the Company's shareholders and to non controlling interests
Beginning Balance	$ 1,006,837
Proceeds from exercise of stock options, value	$ 979
Proceeds from exercise of stock options, shares	50
Tax deficiency related to equity compensation	$ (818)
Stock-based compensation expense	3,241
Restricted stock granted, value	0
Restricted stock canceled	0
Dividends paid	(48,507)
Shares withheld for net settlements of share-based awards	(1,717)
Other adjustments to additional paid-in-capital	179
Issuance of common stock (ESPP), value	107
Net income	32,326	$ 28,756
Other comprehensive (loss) income	(898)	$ (5,721)
Ending Balance	991,729
Common shares
Changes in shareholders' equity that are attributable to the Company's shareholders and to non controlling interests
Beginning Balance	$ 747
Beginning Balance, shares	74,643
Proceeds from exercise of stock options, value	$ 0
Proceeds from exercise of stock options, shares	50
Restricted stock granted, value	$ 3
Restricted stock granted, shares	344
Restricted stock canceled	$ 0
Restricted stock canceled (shares)	(37)
Shares withheld for net settlements of share-based awards (shares)	(57)
Issuance of common stock (ESPP), shares	4
Ending Balance	$ 750
Ending Balance, shares	74,947
Additional Paid-In Capital
Changes in shareholders' equity that are attributable to the Company's shareholders and to non controlling interests
Beginning Balance	$ 879,599
Proceeds from exercise of stock options, value	979
Tax deficiency related to equity compensation	(818)
Stock-based compensation expense	3,241
Restricted stock granted, value	(3)
Shares withheld for net settlements of share-based awards	(1,717)
Other adjustments to additional paid-in-capital	179
Issuance of common stock (ESPP), value	107
Ending Balance	881,567
Earnings in Excess of Distributions
Changes in shareholders' equity that are attributable to the Company's shareholders and to non controlling interests
Beginning Balance	158,796
Dividends paid	(48,507)
Net income	32,350
Other comprehensive (loss) income	0
Ending Balance	142,639
Accumulated Other Comprehensive Loss
Changes in shareholders' equity that are attributable to the Company's shareholders and to non controlling interests
Beginning Balance	(32,404)
Other comprehensive (loss) income	(906)
Ending Balance	(33,310)
Noncontrolling Interests
Changes in shareholders' equity that are attributable to the Company's shareholders and to non controlling interests
Beginning Balance	99
Net income	(24)
Other comprehensive (loss) income	8
Ending Balance	$ 83