CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020 USD ($) Lease	Jun. 30, 2020 USD ($) Lease shares	Jun. 30, 2019 USD ($) shares	Jan. 01, 2019 USD ($)
Supplemental disclosures of non-cash investing and financing activities
Common stock issued through the dividend reinvestment plan (in shares) | shares		1,183	1,092
Common stock issued through the dividend reinvestment plan		$ 217	$ 208
Number of shares withheld to satisfy employees' tax withholding and other liabilities (in shares) | shares		73,089	75,195
Shares withheld to satisfy employees' tax withholding and other liabilities, value		$ 14,750	$ 14,206
Stock issued during period, shares, share-based compensation, forfeited (in shares) | shares		4,050
Stock issued during period, value, share-based compensation, forfeited		$ 685	250
Dividends declared but not paid	$ 226,126	226,126
Change in redemption value of redeemable noncontrolling interest	146
Cash flow hedge losses reclassified to earnings	2,301	4,250	3,079
Operating Lease, Right-of-Use Asset	138,113	138,113
Total lease liabilities	163,321	163,321
Increase (Decrease) in Derivative Liabilities		(98)	4,198
Increase (Decrease) in Derivative Assets		$ 178	$ 18
Restricted Stock and Restricted Stock Converted From Performance Shares
Supplemental disclosures of non-cash investing and financing activities
Equity instruments granted (in shares) | shares		164,526	150,359
Restricted Stock Converted From Performance Shares
Supplemental disclosures of non-cash investing and financing activities
Equity instruments granted (in shares) | shares		96,317	73,072
Restricted stock
Supplemental disclosures of non-cash investing and financing activities
Equity instruments granted (in shares) | shares		68,209	77,287
Fair value of shares issued		$ 15,150	$ 15,145
Stock issued during period, shares, share-based compensation, forfeited (in shares) | shares		4,050	1,438
Common stock
Supplemental disclosures of non-cash investing and financing activities
Dividends declared but not paid	224,482	$ 224,482	$ 212,822
Accumulated earnings less dividends
Supplemental disclosures of non-cash investing and financing activities
Change in redemption value of redeemable noncontrolling interest	146	(325)	$ 269
Accounting Standards Update 2016-02
Supplemental disclosures of non-cash investing and financing activities
Operating Lease, Right-of-Use Asset				$ 122,276
Total lease liabilities				$ 122,276
New Office Leases
Supplemental disclosures of non-cash investing and financing activities
Operating Lease, Right-of-Use Asset	$ 46,875	$ 46,875
Number of New Office Leases | Lease	2	2
Total lease liabilities	$ 46,875	$ 46,875