Condensed Consolidating Financial Information (Statements of Cash Flows) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	$ 78,825	$ 83,885
Cash flows from investing activities:
Sale of investment securities	67,033	118,261
Maturities of investment securities	343	1,737
Purchase of investment securities	(56,691)	(113,595)
Purchase of long-term investments	(50)	(5,000)
Proceeds from sale or liquidation of long-term investments	1,000	1,254
Investments in real estate ventures	(11,806)	(34,857)
Distributions from investments in real estate ventures	17,983	0
Increase in cash surrender value of life insurance policies	(393)	(1,118)
Decrease (increase) in restricted assets	2,674	(7,934)
Issuance of notes receivable	0	(4,410)
Investments in subsidiaries	0	0
Proceeds from sale of preferred securities	0	1,000
Proceeds from sale of fixed assets	5	3
Capital expenditures	(7,615)	(5,379)
Pay downs of investment securities	4,926	3,530
Investments in real estate, net	(81)	(12,502)
Net cash provided by (used in) investing activities	17,328	(59,010)
Cash flows from financing activities:
Proceeds from issuance of debt	243,282	22
Deferred financing costs	(6,600)	(625)
Repayments of debt	(2,917)	(3,374)
Borrowings under revolver	89,695	126,727
Repayments on revolver	(80,223)	(144,492)
Capital contributions received	0	0
Intercompany dividends paid	0	0
Dividends and distributions on common stock	(97,846)	(92,778)
Contributions from non-controlling interest	248	0
Distributions to non-controlling interest	(7,422)	0
Proceeds from exercise of Vector options	0	1,219
Tax benefit of options exercised	0	384
Net cash provided by (used in) financing activities	138,217	(112,917)
Net increase (decrease) in cash and cash equivalents	234,370	(88,042)
Cash and cash equivalents, beginning of period	240,368	326,365
Cash and cash equivalents, end of period	474,738	238,323
Consolidating Adjustments [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	(99,040)	(71,010)
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
Increase in cash surrender value of life insurance policies	0	0
Decrease (increase) in restricted assets	0	0
Issuance of notes receivable		0
Investments in subsidiaries	987	42,808
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 provided by (used in) investing activities	987	42,808
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	(987)	(42,808)
Intercompany dividends paid	99,040	71,010
Dividends and distributions on common stock	0	0
Contributions from non-controlling interest	0
Distributions to non-controlling interest	0
Proceeds from exercise of Vector options		0
Tax benefit of options exercised		0
Net cash provided by (used in) financing activities	98,053	28,202
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	73,915	42,679
Cash flows from investing activities:
Sale of investment securities	62,312	103,846
Maturities of investment securities	343	1,737
Purchase of investment securities	(56,691)	(112,119)
Purchase of long-term investments	0	(5,000)
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
Increase in cash surrender value of life insurance policies	0	(717)
Decrease (increase) in restricted assets	(7)	(1,327)
Issuance of notes receivable		0
Investments in subsidiaries	(987)	(42,808)
Proceeds from sale of preferred securities		0
Proceeds from sale of fixed assets	0	0
Capital expenditures	(26)	0
Pay downs of investment securities	4,926	3,530
Investments in real estate, net	0	0
Net cash provided by (used in) investing activities	10,870	(51,752)
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	(97,846)	(92,778)
Contributions from non-controlling interest	0
Distributions to non-controlling interest	0
Proceeds from exercise of Vector options		1,219
Tax benefit of options exercised		384
Net cash provided by (used in) financing activities	138,779	(91,175)
Net increase (decrease) in cash and cash equivalents	223,564	(100,248)
Cash and cash equivalents, beginning of period	111,470	211,751
Cash and cash equivalents, end of period	335,034	111,503
Subsidiary Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	75,513	99,159
Cash flows from investing activities:
Sale of investment securities	4,721	14,415
Maturities of investment securities	0	0
Purchase of investment securities	0	(1,476)
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
Increase in cash surrender value of life insurance policies	(393)	(401)
Decrease (increase) in restricted assets	2,181	(6,607)
Issuance of notes receivable		0
Investments in subsidiaries	0	0
Proceeds from sale of preferred securities		0
Proceeds from sale of fixed assets	4	3
Capital expenditures	(3,716)	(2,350)
Pay downs of investment securities	0	0
Investments in real estate, net	0	0
Net cash provided by (used in) investing activities	2,797	3,584
Cash flows from financing activities:
Proceeds from issuance of debt	0	22
Deferred financing costs	0	(625)
Repayments of debt	(2,863)	(3,254)
Borrowings under revolver	89,695	126,727
Repayments on revolver	(80,223)	(144,492)
Capital contributions received	600	2,250
Intercompany dividends paid	(65,648)	(69,075)
Dividends and distributions on common stock	0	0
Contributions from non-controlling interest	0
Distributions to non-controlling interest	0
Proceeds from exercise of Vector options		0
Tax benefit of options exercised		0
Net cash provided by (used in) financing activities	(58,439)	(88,447)
Net increase (decrease) in cash and cash equivalents	19,871	14,296
Cash and cash equivalents, beginning of period	12,375	9,724
Cash and cash equivalents, end of period	32,246	24,020
Subsidiary Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Net cash provided by operating activities	28,437	13,057
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	148
Investments in real estate ventures	(11,806)	(34,857)
Distributions from investments in real estate ventures	17,983
Increase in cash surrender value of life insurance policies	0	0
Decrease (increase) in restricted assets	500	0
Issuance of notes receivable		(4,410)
Investments in subsidiaries	0	0
Proceeds from sale of preferred securities		1,000
Proceeds from sale of fixed assets	1	0
Capital expenditures	(3,873)	(3,029)
Pay downs of investment securities	0	0
Investments in real estate, net	(81)	(12,502)
Net cash provided by (used in) investing activities	2,674	(53,650)
Cash flows from financing activities:
Proceeds from issuance of debt	57	0
Deferred financing costs	0	0
Repayments of debt	(54)	(120)
Borrowings under revolver	0	0
Repayments on revolver	0	0
Capital contributions received	387	40,558
Intercompany dividends paid	(33,392)	(1,935)
Dividends and distributions on common stock	0	0
Contributions from non-controlling interest	248
Distributions to non-controlling interest	(7,422)
Proceeds from exercise of Vector options		0
Tax benefit of options exercised		0
Net cash provided by (used in) financing activities	(40,176)	38,503
Net increase (decrease) in cash and cash equivalents	(9,065)	(2,090)
Cash and cash equivalents, beginning of period	116,523	104,890
Cash and cash equivalents, end of period	$ 107,458	$ 102,800