Income Taxes (Tax Treatment of Distributions and Consolidated Benefit for Income Taxes) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Tax treatment of distributions:
Ordinary income (in dollars per share)									$ 0	$ 0	$ 0
Qualified ordinary income (in dollars per share)									0.00696	0.12230	0.00375
199A qualified business income									2.14381	2.22898	2.97465
Long-term capital gain (in dollars per share)									0.28450	0	0.05916
Unrecaptured Section 1250 gain (in dollars per share)									0.04973	0.03434	0.12244
Tax Treatment Of Non-dividend Distributions									0	0.78438	0
Distribution reported for 1099-DIV purposes (in dollars per share)									2.48500	3.17000	3.16000
Add: Dividend declared in current year and taxable in following year (in dollars per share)	$ 0.4500										0.79250
Less: Dividend declared in prior year and taxable in current year									(0.79250)	(0.79250)	(0.79000)
Dividends declared per common share (in dollars per share)		$ 0.4500	$ 0.4500	$ 0.7925	$ 0.7925	$ 0.7925	$ 0.7925	$ 0.7925	$ 2.14250	$ 3.17000	$ 3.16250
Provision (benefit) for income taxes
Current - Federal									$ 402	$ (1,840)	$ (2,953)
Current - State									2,107	2,118	1,332
Deferred - Federal									(56,835)	(49,532)	(32,492)
Deferred - State									(35,447)	(3,353)	(825)
Current - Foreign									2,929	2,335	1,892
Deferred - Foreign									(9,690)	(6,038)	(6,907)
Income tax benefit									$ (96,534)	$ (56,310)	$ (39,953)