Investments Investments, Other Investments (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Schedule of Cost-method Investments [Line Items]
Available-for-sale Securities, Amortized Cost Basis	$ 527,183	$ 450,074
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	7,598	6,577
Fair Value of Limited Partnership Interest	5,433
Available-for-sale Securities, Gross Unrealized Loss, Accumulated in Investments	6,134	3,937
DCR Mortgage Fund VI, L.P.
Schedule of Cost-method Investments [Line Items]
Fair Value of Limited Partnership Interest	711
RCH Mortgage Fund VI, L.P.
Schedule of Cost-method Investments [Line Items]
Fair Value of Limited Partnership Interest	987
Kayne Senior Credit Fund II, L.P.
Schedule of Cost-method Investments [Line Items]
Fair Value of Limited Partnership Interest	1,450
DCR Mortgage Fund VII, L.P.
Schedule of Cost-method Investments [Line Items]
Fair Value of Limited Partnership Interest	2,045
Blackstone Alternative Solutions Trust 2015
Schedule of Cost-method Investments [Line Items]
Fair Value of Limited Partnership Interest	240
Limited Partner
Schedule of Cost-method Investments [Line Items]
Payments to Acquire Limited Partnership Interests	5,197
Available-for-sale Securities, Amortized Cost Basis	5,193
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	267
Fair Value of Limited Partnership Interest	5,433
Available-for-sale Securities, Gross Unrealized Loss, Accumulated in Investments	27
Certificates of Deposit
Schedule of Cost-method Investments [Line Items]
Available-for-sale Securities, Amortized Cost Basis	300
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0
Payments to Acquire Restricted Certificates of Deposit	300
Certificates of Deposit, at Carrying Value	300
Available-for-sale Securities, Gross Unrealized Loss, Accumulated in Investments	0
Other Long-term Investments
Schedule of Cost-method Investments [Line Items]
Available-for-sale Securities, Amortized Cost Basis	5,493	4,980
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	267	230
Cost Method Investments	5,497
Other Long-term Investments	5,733	5,210
Available-for-sale Securities, Gross Unrealized Loss, Accumulated in Investments	27	$ 0
Other Long-term Investments \| Limited Partner \| Kayne Senior Credit Fund II, L.P.
Schedule of Cost-method Investments [Line Items]
Payments to Acquire Other Investments	425
Other Long-term Investments \| Limited Partner \| Blackstone Alternative Solutions Trust 2015
Schedule of Cost-method Investments [Line Items]
Payments to Acquire Other Investments	760
Fair Value, Inputs, Level 3 \| Limited Partner
Schedule of Cost-method Investments [Line Items]
Payments to Acquire Limited Partnership Interests	1,382
Available-for-sale Securities, Amortized Cost Basis	1,458
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	267
Fair Value of Limited Partnership Interest	1,698
Available-for-sale Securities, Gross Unrealized Loss, Accumulated in Investments	27
Fair Value, Inputs, Level 3 \| Other Long-term Investments \| Limited Partner \| DCR Mortgage Fund VI, L.P.
Schedule of Cost-method Investments [Line Items]
Payments to Acquire Limited Partnership Interests	382
Available-for-sale Securities, Amortized Cost Basis	444
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	267
Available-for-sale Securities, Gross Unrealized Loss, Accumulated in Investments	0
Fair Value, Inputs, Level 3 \| Other Long-term Investments \| Limited Partner \| RCH Mortgage Fund VI, L.P.
Schedule of Cost-method Investments [Line Items]
Payments to Acquire Limited Partnership Interests	1,000
Available-for-sale Securities, Amortized Cost Basis	1,014
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0
Available-for-sale Securities, Gross Unrealized Loss, Accumulated in Investments	27
Level 2 \| Limited Partner
Schedule of Cost-method Investments [Line Items]
Payments to Acquire Limited Partnership Interests	3,815
Available-for-sale Securities, Amortized Cost Basis	3,735
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0
Fair Value of Limited Partnership Interest	3,735
Available-for-sale Securities, Gross Unrealized Loss, Accumulated in Investments	0
Level 2 \| Other Long-term Investments \| Limited Partner \| Kayne Senior Credit Fund II, L.P.
Schedule of Cost-method Investments [Line Items]
Payments to Acquire Limited Partnership Interests	1,575
Available-for-sale Securities, Amortized Cost Basis	1,450
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0
Available-for-sale Securities, Gross Unrealized Loss, Accumulated in Investments	0
Level 2 \| Other Long-term Investments \| Limited Partner \| DCR Mortgage Fund VII, L.P.
Schedule of Cost-method Investments [Line Items]
Available-for-sale Securities, Amortized Cost Basis	2,045
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0
Payments to Acquire Other Investments	2,000
Available-for-sale Securities, Gross Unrealized Loss, Accumulated in Investments	0
Level 2 \| Other Long-term Investments \| Limited Partner \| Blackstone Alternative Solutions Trust 2015
Schedule of Cost-method Investments [Line Items]
Available-for-sale Securities, Amortized Cost Basis	240
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	0
Payments to Acquire Other Investments	240
Available-for-sale Securities, Gross Unrealized Loss, Accumulated in Investments	$ 0

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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A savings certificate entitling the Entity (that is, bearer) to receive interest at an established maturity date, based upon a fixed interest rate. A certificate of deposit may be issued in any denomination. Certificates of deposit are generally issued by commercial banks and, therefore, insured by the FDIC (up to the prescribed limit). Certificates of deposit generally restrict holders from withdrawing funds on demand without the incurrence of penalties. Generally, only certificates of deposit with original maturities of three months or less qualify as cash equivalents. Original maturity means original maturity to the entity holding the investment. As a related example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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Amount, after adjustment, of cost-method investment. Adjustments include, but are not limited to, dividends received in excess of earnings after date of investment that are considered a return of investment and other than temporary impairments.

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Amount of long-term investments classified as other.

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