Consolidated Statement Of Equity - USD ($)	Total	Revision of Prior Period, Accounting Standards Update, Adjustment	Common Stock [Member]	Common Stock [Member] At-The-Market	Additional Paid-in Capital [Member]	Cumulative Dividends In Excess Of Net Income [Member]	Cumulative Dividends In Excess Of Net Income [Member] Revision of Prior Period, Accounting Standards Update, Adjustment	Accumulated Other Comprehensive Income (Loss) [Member]	Parent [Member]	Parent [Member] Revision of Prior Period, Accounting Standards Update, Adjustment	Noncontrolling Interest [Member]
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,498,252,000		$ 446,000		$ 1,505,948,000	$ (5,331,000)		$ (3,432,000)	$ 1,497,631,000		$ 621,000
Balance, shares at Dec. 31, 2019			44,587,486
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Issued During Period, Shares, New Issues	0
Noncontrolling Interest, Increase from Subsidiary Equity Issuance	$ 10,791,000										10,791,000
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders											16,000
Net income (loss) attributable to common stockholders	61,023,000					61,023,000		(8,699,000)	52,324,000
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	39,000										39,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	52,363,000
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture			62,516
Stock Issued During Period, Value, New Issues	85,000		$ 0		85,000				85,000		0
Share-based Payment Arrangement, Decrease for Tax Withholding Obligation	(2,705,000)				2,705,000				2,705,000		0
Stock Issued During Period, Value, Stock Options Exercised	1,000		$ 1,000		2,000				1,000
Share-based compensation	1,845,000				1,845,000				1,845,000		0
Dividends declared, $1.54 per share	(49,226,000)					(49,226,000)			(49,226,000)		0
Balance, shares at Mar. 31, 2020			44,650,002
Balance, shares at Dec. 31, 2019			44,587,486
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Noncontrolling Interest, Increase from Subsidiary Equity Issuance	$ 0										0
Balance, shares at Dec. 31, 2020	45,185,992		45,185,992
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,506,993,000		$ 447,000		1,505,001,000	2,241,000		(12,131,000)	1,495,558,000		11,435,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Retained Earnings (Accumulated Deficit)							$ (4,225,000)
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,522,945,000		$ 452,000		1,540,946,000	(22,015,000)		(7,149,000)	1,512,234,000		10,711,000
Stock Issued During Period, Shares, New Issues	661,951			661,951
Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders	$ (233,000)										233,000
Net income (loss) attributable to common stockholders	35,332,000					35,332,000		1,772,000	37,104,000
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest	52,000										52,000
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	37,156,000
Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture			2,656
Stock Issued During Period, Value, New Issues	(47,951,000)		$ (7,000)		(47,944,000)				(47,951,000)
Stock Issued During Period, Value, Stock Options Exercised	0		$ 0		0				0
Share-based compensation	5,446,000				5,446,000				5,446,000
Dividends declared, $1.54 per share	$ (50,550,000)					(50,550,000)			(50,550,000)
Balance, shares at Mar. 31, 2021	45,850,599		45,850,599
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	$ 1,562,715,000		$ 459,000		$ 1,594,336,000	$ (37,233,000)		$ (5,377,000)	$ 1,552,185,000		$ 10,530,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Retained Earnings (Accumulated Deficit)		$ 0					$ 0			$ 0