Equity - Changes in Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2022	Sep. 30, 2021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period (in shares)			53,716,000				53,716,000
Balance at beginning of period	$ 1,207,306	$ 1,169,878	$ 1,182,980	$ 1,002,263	$ 929,802	$ 921,344	$ 1,182,980	$ 921,344
Net income (loss)	55,683	19,215	894	62,499	38,076	(3,032)	$ 75,792	97,543
Issuance of common stock	29,038	32,124	1,107	67,830	40,902	24,486
Repurchase of common stock	(105)	(111)	(1,674)	(69)	(109)	(1,415)
Dividends paid on common stock	(13,590)	(13,452)	(13,429)	(11,863)	(11,702)	(11,581)
Investment in business with noncontrolling interest	$ 0	0	0	0
Acquisition of business with noncontrolling interest					5,294
Distribution to noncontrolling interest		(348)
Balance at end of period (in shares)	54,824,000						54,824,000
Balance at end of period	$ 1,278,332	$ 1,207,306	$ 1,169,878	$ 1,120,660	$ 1,002,263	$ 929,802	$ 1,278,332	$ 1,120,660
Dividends paid on common stock (in dollars per share)	$ 0.2500	$ 0.2500	$ 0.2500	$ 0.2300	$ 0.2300	$ 0.2300
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period (in shares)	54,356,000	53,773,000	53,716,000	51,535,000	50,835,000	50,334,000	53,716,000	50,334,000
Balance at beginning of period	$ 544	$ 538	$ 537	$ 515	$ 508	$ 503	$ 537	$ 503
Issuance of common stock (in shares)	470,000	585,000	85,000	1,075,000	702,000	528,000
Issuance of common stock	$ 4	$ 6	$ 1	$ 11	$ 7	$ 5
Repurchase of common stock (in shares)	(2,000)	(2,000)	(28,000)	(2,000)	(2,000)	(27,000)
Balance at end of period (in shares)	54,824,000	54,356,000	53,773,000	52,608,000	51,535,000	50,835,000	54,824,000	52,608,000
Balance at end of period	$ 548	$ 544	$ 538	$ 526	$ 515	$ 508	$ 548	$ 526
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	682,353	650,499	651,121	512,484	471,698	448,632	651,121	448,632
Issuance of common stock	29,034	32,118	1,106	67,819	40,895	24,481
Repurchase of common stock	(105)	(111)	(1,674)	(69)	(109)	(1,415)
Investment in business with noncontrolling interest	(278)	(153)	(54)	526
Balance at end of period	711,004	682,353	650,499	580,760	512,484	471,698	711,004	580,760
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	519,625	513,593	525,936	484,119	457,596	472,209	525,936	472,209
Net income (loss)	55,872	19,484	1,086	62,429	38,225	(3,032)
Dividends paid on common stock	(13,590)	(13,452)	(13,429)	(11,863)	(11,702)	(11,581)
Balance at end of period	561,907	519,625	513,593	534,685	484,119	457,596	561,907	534,685
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	4,784	5,248	5,386	5,145	0	0	5,386	0
Net income (loss)	(189)	(269)	(192)	70	(149)
Investment in business with noncontrolling interest	278	153	54	(526)
Acquisition of business with noncontrolling interest					5,294
Distribution to noncontrolling interest		(348)
Balance at end of period	$ 4,873	$ 4,784	$ 5,248	$ 4,689	$ 5,145	$ 0	$ 4,873	$ 4,689