Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Statement of Cash Flows [Abstract]
Net cash provided by operating activities	$ 209,808	$ 206,443
Cash flows from investing activities:
Sale of investment securities	14,895	23,066
Maturities of investment securities	16,899	94,858
Purchase of investment securities	(22,516)	(120,362)
Proceeds from sale or liquidation of long-term investments	0	966
Purchase of long-term investments	0	(26,500)
Investments in real estate ventures	(6,132)	(20,830)
Distributions from investments in real estate ventures	37,819	23,338
Increase in cash surrender value of life insurance policies	(806)	(831)
Decrease in restricted assets	254	2,112
Issuance of notes receivable	0	(1,633)
Proceeds from sale of fixed assets	0	75
Capital expenditures	(12,546)	(15,258)
Repayments of notes receivable	67	0
Acquisition of a business	(370)	(6,569)
Pay downs of investment securities	1,293	2,153
Investments in real estate, net	(1,495)	(357)
Net cash provided by (used in) investing activities	27,362	(45,772)
Cash flows from financing activities:
Proceeds from issuance of debt	0	850,021
Deferred financing costs	0	(19,200)
Repayments of debt	(1,490)	(836,600)
Borrowings under revolver	261,058	121,521
Repayments on revolver	(264,654)	(152,870)
Dividends and distributions on common stock	(169,571)	(158,425)
Distributions to non-controlling interest	(2,521)	(165)
Proceeds from issuance of Vector common stock	0	43,230
Net cash used in financing activities	(177,178)	(152,488)
Net increase in cash, cash equivalents and restricted cash	59,992	8,183
Cash, cash equivalents and restricted cash, beginning of period	310,937	398,578
Cash, cash equivalents and restricted cash, end of period	$ 370,929	$ 406,761