Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Statement of Cash Flows [Abstract]
Net cash provided by operating activities	$ 122,426	$ 117,611
Cash flows from investing activities:
Sale of investment securities	2,647	22,396
Maturities of investment securities	10,598	93,368
Purchase of investment securities	(12,402)	(109,891)
Proceeds from sale or liquidation of long-term investments	0	466
Purchase of long-term investments	0	(26,000)
Investments in real estate ventures	(4,343)	(8,454)
Distributions from investments in real estate ventures	27,134	23,338
Increase in cash surrender value of life insurance policies	(809)	(854)
Decrease in restricted assets	262	2,545
Issuance of notes receivable	0	(1,500)
Proceeds from sale of fixed assets	0	75
Capital expenditures	(8,616)	(8,346)
Repayments of notes receivable	32	0
Acquisition of a business	(403)	0
Pay downs of investment securities	928	1,620
Investments in real estate, net	(1,009)	(205)
Net cash provided by (used in) investing activities	14,019	(11,442)
Cash flows from financing activities:
Proceeds from issuance of debt	0	850,020
Deferred financing costs	0	(19,200)
Repayments of debt	(987)	(836,145)
Borrowings under revolver	134,310	110,979
Repayments on revolver	(137,877)	(129,479)
Dividends and distributions on common stock	(112,462)	(104,750)
Distributions to non-controlling interest	(359)	(165)
Proceeds from issuance of Vector common stock	0	43,230
Net cash used in financing activities	(117,375)	(85,510)
Net increase in cash, cash equivalents and restricted cash	19,070	20,659
Cash, cash equivalents and restricted cash, beginning of period	310,937	398,578
Cash, cash equivalents and restricted cash, end of period	$ 330,007	$ 419,237