Condensed Consolidating Financial Information (Statements of Cash Flows) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	$ 121,443	$ 140,018
Cash flows from investing activities:
Sale of investment securities	81,235	161,029
Maturities of investment securities	4,343	2,653
Purchase of investment securities	(90,106)	(162,845)
Purchase of long-term investments	(50)	(10,000)
Proceeds from sale or liquidation of long-term investments	1,000	1,288
Investments in real estate ventures	(23,358)	(43,280)
Distributions from investments in real estate ventures	23,041	11,205
Increase in cash surrender value of life insurance policies	(451)	(1,225)
Decrease (increase) in restricted assets	8,615	(6,872)
Issuance of notes receivable	0	(4,410)
Repayments of notes receivable	4,410	4,000
Investments in subsidiaries	0	0
Proceeds from sale of preferred securities	0	1,000
Proceeds from sale of fixed assets	45	3
Capital expenditures	(19,157)	(7,859)
Pay downs of investment securities	7,842	5,743
Investments in real estate, net	(130)	(12,512)
Net cash used in investing activities	(2,721)	(62,082)
Cash flows from financing activities:
Proceeds from issuance of debt	243,620	1,519
Deferred financing costs	(6,600)	(624)
Repayments of debt	(4,698)	(4,968)
Borrowings under revolver	104,826	130,691
Repayments on revolver	(94,644)	(146,655)
Capital contributions received	0	0
Intercompany dividends paid	0	0
Dividends and distributions on common stock	(147,270)	(139,430)
Contributions from non-controlling interest	248	0
Distributions to non-controlling interest	(9,508)	(564)
Proceeds from exercise of Vector options	398	1,321
Tax benefit of options exercised	412	756
Net cash provided by (used in) financing activities	86,784	(157,954)
Net increase (decrease) in cash and cash equivalents	205,506	(80,018)
Cash and cash equivalents, beginning of period	240,368	326,365
Cash and cash equivalents, end of period	445,874	246,347
Consolidating Adjustments [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	(156,635)	(144,569)
Cash flows from investing activities:
Sale of investment securities	0	0
Maturities of investment securities	0	0
Purchase of investment securities	0	0
Purchase of long-term investments	0	0
Proceeds from sale or liquidation of long-term investments	0	0
Investments in real estate ventures	0	0
Distributions from investments in real estate ventures	0	0
Increase in cash surrender value of life insurance policies	0	0
Decrease (increase) in restricted assets	0	0
Issuance of notes receivable		0
Repayments of notes receivable	0	0
Investments in subsidiaries	1,103	53,511
Proceeds from sale of fixed assets	0	0
Capital expenditures	0	0
Pay downs of investment securities	0	0
Investments in real estate, net	0	0
Net cash used in investing activities	1,103	53,511
Cash flows from financing activities:
Proceeds from issuance of debt	0	0
Deferred financing costs	0	0
Repayments of debt	0	0
Borrowings under revolver	0	0
Repayments on revolver	0	0
Capital contributions received	(1,103)	(53,511)
Intercompany dividends paid	156,635	144,569
Dividends and distributions on common stock	0	0
Contributions from non-controlling interest	0
Distributions to non-controlling interest	0	0
Proceeds from exercise of Vector options	0	0
Tax benefit of options exercised	0	0
Net cash provided by (used in) financing activities	155,532	91,058
Net increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents, beginning of period	0	0
Cash and cash equivalents, end of period	0	0
Parent/Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	87,016	84,832
Cash flows from investing activities:
Sale of investment securities	76,514	146,614
Maturities of investment securities	4,343	2,653
Purchase of investment securities	(90,106)	(156,521)
Purchase of long-term investments	0	(10,000)
Proceeds from sale or liquidation of long-term investments	1,000	1,106
Investments in real estate ventures	0	0
Distributions from investments in real estate ventures	0	0
Increase in cash surrender value of life insurance policies	0	(766)
Decrease (increase) in restricted assets	(11)	(2)
Issuance of notes receivable		0
Repayments of notes receivable	0	0
Investments in subsidiaries	(1,103)	(53,511)
Proceeds from sale of preferred securities		0
Proceeds from sale of fixed assets	0	0
Capital expenditures	(33)	0
Pay downs of investment securities	7,842	5,743
Investments in real estate, net	0	0
Net cash used in investing activities	(1,554)	(64,684)
Cash flows from financing activities:
Proceeds from issuance of debt	243,225	0
Deferred financing costs	(6,600)	0
Repayments of debt	0	0
Borrowings under revolver	0	0
Repayments on revolver	0	0
Capital contributions received	0	0
Intercompany dividends paid	0	0
Dividends and distributions on common stock	(147,270)	(139,430)
Contributions from non-controlling interest	0
Distributions to non-controlling interest	0	0
Proceeds from exercise of Vector options	398	1,321
Tax benefit of options exercised	412	756
Net cash provided by (used in) financing activities	90,165	(137,353)
Net increase (decrease) in cash and cash equivalents	175,627	(117,205)
Cash and cash equivalents, beginning of period	111,470	211,751
Cash and cash equivalents, end of period	287,097	94,546
Subsidiary Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	136,255	168,095
Cash flows from investing activities:
Sale of investment securities	4,721	14,415
Maturities of investment securities	0	0
Purchase of investment securities	0	(6,324)
Purchase of long-term investments	0	0
Proceeds from sale or liquidation of long-term investments	0	0
Investments in real estate ventures	0	0
Distributions from investments in real estate ventures	0	0
Increase in cash surrender value of life insurance policies	(451)	(459)
Decrease (increase) in restricted assets	8,126	(6,870)
Issuance of notes receivable		0
Repayments of notes receivable	0	0
Investments in subsidiaries	0	0
Proceeds from sale of preferred securities		0
Proceeds from sale of fixed assets	32	3
Capital expenditures	(5,619)	(3,305)
Pay downs of investment securities	0	0
Investments in real estate, net	0	0
Net cash used in investing activities	6,809	(2,540)
Cash flows from financing activities:
Proceeds from issuance of debt	0	1,519
Deferred financing costs	0	(624)
Repayments of debt	(4,602)	(4,786)
Borrowings under revolver	104,826	130,691
Repayments on revolver	(94,644)	(146,655)
Capital contributions received	700	5,633
Intercompany dividends paid	(116,785)	(134,215)
Dividends and distributions on common stock	0	0
Contributions from non-controlling interest	0
Distributions to non-controlling interest	0	0
Proceeds from exercise of Vector options	0	0
Tax benefit of options exercised	0	0
Net cash provided by (used in) financing activities	(110,505)	(148,437)
Net increase (decrease) in cash and cash equivalents	32,559	17,118
Cash and cash equivalents, beginning of period	12,375	9,724
Cash and cash equivalents, end of period	44,934	26,842
Subsidiary Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	54,807	31,660
Cash flows from investing activities:
Sale of investment securities	0	0
Maturities of investment securities	0	0
Purchase of investment securities	0	0
Purchase of long-term investments	(50)	0
Proceeds from sale or liquidation of long-term investments	0	182
Investments in real estate ventures	(23,358)	(43,280)
Distributions from investments in real estate ventures	23,041	11,205
Increase in cash surrender value of life insurance policies	0	0
Decrease (increase) in restricted assets	500	0
Issuance of notes receivable		(4,410)
Repayments of notes receivable	4,410	4,000
Investments in subsidiaries	0	0
Proceeds from sale of preferred securities		1,000
Proceeds from sale of fixed assets	13	0
Capital expenditures	(13,505)	(4,554)
Pay downs of investment securities	0	0
Investments in real estate, net	(130)	(12,512)
Net cash used in investing activities	(9,079)	(48,369)
Cash flows from financing activities:
Proceeds from issuance of debt	395	0
Deferred financing costs	0	0
Repayments of debt	(96)	(182)
Borrowings under revolver	0	0
Repayments on revolver	0	0
Capital contributions received	403	47,878
Intercompany dividends paid	(39,850)	(10,354)
Dividends and distributions on common stock	0	0
Contributions from non-controlling interest	248
Distributions to non-controlling interest	(9,508)	(564)
Proceeds from exercise of Vector options	0	0
Tax benefit of options exercised	0	0
Net cash provided by (used in) financing activities	(48,408)	36,778
Net increase (decrease) in cash and cash equivalents	(2,680)	20,069
Cash and cash equivalents, beginning of period	116,523	104,890
Cash and cash equivalents, end of period	$ 113,843	$ 124,959