Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period (in shares)	50,334,000
Balance at beginning of period	$ 921,344	$ 779,906
Net loss	(3,032)	(20,307)
Issuance of common stock	24,486	7,229
Repurchase of common stock	(1,415)	(1,373)
Dividends paid on common stock	$ (11,581)	(10,315)
Balance at end of period (in shares)	50,835,000
Balance at end of period	$ 929,802	$ 755,140
Dividends paid on common stock (in dollars per share)	$ 0.2300	$ 0.2125
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period (in shares)	50,334,000	48,532,000
Balance at beginning of period	$ 503	$ 485
Issuance of common stock (in shares)	528,000	210,000
Issuance of common stock	$ 5	$ 2
Repurchase of common stock (in shares)	(27,000)	(28,000)
Balance at end of period (in shares)	50,835,000	48,714,000
Balance at end of period	$ 508	$ 487
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	448,632	362,275
Issuance of common stock	24,481	7,227
Repurchase of common stock	(1,415)	(1,373)
Balance at end of period	471,698	368,129
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance at beginning of period	472,209	417,146
Net loss	(3,032)	(20,307)
Dividends paid on common stock	(11,581)	(10,315)
Balance at end of period	$ 457,596	$ 386,524