Investments (Tables)

9 Months Ended

Sep. 30, 2017

Investments, Debt and Equity Securities [Abstract]

Available For Sale Securities

Following is a summary of AFS securities as of September 30, 2017 and December 31, 2016:

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
	(Amounts are in thousands)
September 30, 2017
Tax exempt bonds	$	2,054,341		5,308		2,841	2,056,808
Taxable bonds	2,185,377			3,639		14,000	2,175,016
Restricted investments	164,548			463		—	165,011
Equity securities	1,971,825			134,123		2,242	2,103,706
	$	6,376,091		143,533		19,083	6,500,541
December 31, 2016
Tax exempt bonds	$	3,036,060		2,211		24,649	3,013,622
Taxable bonds	2,469,192			1,359		33,903	2,436,648
Restricted investments	164,548			—		463	164,085
Equity securities	1,021,340			110,879		7,956	1,124,263
	$	6,691,140		114,449		66,971	6,738,618

Amortized Cost and Fair Value of Available For Sale Securities by Expected Maturity

The amortized cost and fair value of AFS securities by expected maturity as of September 30, 2017 and December 31, 2016 are as follows:

	September 30, 2017			December 31, 2016
	Amortized Cost		Fair Value	Amortized Cost	Fair Value
	(Amounts are in thousands)
Due in one year or less	$	1,256,912	1,256,724	1,592,144	1,591,740
Due after one year through five years	2,583,254		2,577,163	3,218,371	3,187,739
Due after five years through ten years	389,425		387,386	680,641	656,162
Due after ten years	10,127		10,551	14,096	14,629
	4,239,718		4,231,824	5,505,252	5,450,270
Restricted investments	164,548		165,011	164,548	164,085
Equity securities	1,971,825		2,103,706	1,021,340	1,124,263
	$	6,376,091	6,500,541	6,691,140	6,738,618

Temporarily Impaired Available For Sale Securities by Time Period Impaired

Following is a summary of temporarily impaired AFS securities by the time period impaired as of September 30, 2017 and December 31, 2016:

	Less Than 12 Months				12 Months or Longer			Total
	Fair Value		Unrealized Losses		Fair Value	Unrealized Losses		Fair Value	Unrealized Losses
	(Amounts are in thousands)
September 30, 2017
Tax exempt bonds	$	510,790		1,699	232,906		1,142	743,696		2,841
Taxable bonds	964,755			5,332	643,454		8,668	1,608,209		14,000
Equity securities	62,700			1,239	3,526		1,003	66,226		2,242
	$	1,538,245		8,270	879,886		10,813	2,418,131		19,083
December 31, 2016
Tax exempt bonds	$	2,360,143		24,416	6,099		233	2,366,242		24,649
Taxable bonds	1,921,367			33,354	51,769		549	1,973,136		33,903
Restricted investments	164,085			463	—		—	164,085		463
Equity securities	61,625			3,924	38,141		4,032	99,766		7,956
	$	4,507,220		62,157	96,009		4,814	4,603,229		66,971