Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2014

Compensation and Retirement Disclosure [Abstract]

Schedule of reconciliation of the changes in the benefit obligations

The following tables provide a reconciliation of the changes in the benefit obligations, fair value of plan assets and the underfunded status for the Company’s Defined Benefit Pension, Post-Retirement Medical and Supplemental Executive Retirement plans:

	Defined Benefit  Pension Plan						Post-Retirement  Medical Plan						Supplemental Executive Retirement Plan						Total
	Year Ended December 31,						Year Ended December 31,						Year Ended December 31,						Year Ended December 31,
	2014			2013			2014			2013			2014			2013			2014			2013
Change in projected benefit obligation:
Benefit obligation, January 1	$	456,402		$	500,603		$	11,081		$	13,462		$	62,305		$	69,229		$	529,788		$	583,294
Service cost	4,952			5,527			985			947			586			1,002			6,523			7,476
Interest cost	23,068			20,897			574			512			2,528			2,548			26,170			23,957
Actuarial (gain) loss	113,410			(57,051		)	(2,092		)	(3,221		)	3,376			(6,791		)	114,694			(67,063		)
Regular benefits paid	(14,752		)	(13,574		)	(508		)	(619		)	(16,874		)	(3,683		)	(32,134		)	(17,876		)
Amendment	—			—			(569		)	—			3,911			—			3,342			—
Acquisition	—			—			3,311			—			—			—			3,311			—
Benefit obligation, December 31	$	583,080		$	456,402		$	12,782		$	11,081		$	55,832		$	62,305		$	651,694		$	529,788
Accumulated benefit obligation	$	562,760		$	440,666		$	12,782		$	11,081		$	50,032		$	54,195		$	625,574		$	505,942

Schedule of fair value of plan assets

	Defined Benefit  Pension Plan						Post-Retirement  Medical Plan						Supplemental Executive Retirement Plan						Total
	Year Ended December 31,						Year Ended December 31,						Year Ended December 31,						Year Ended December 31,
	2014			2013			2014			2013			2014			2013			2014			2013
Change in plan assets:
Value of plan assets, January 1	$	404,335		$	336,534		$	—		$	—		$	—		$	—		$	404,335		$	336,534
Actual return on plan assets	43,662			62,701			—			—			—			—			43,662			62,701
Employer contributions	10,717			18,674			508			619			16,874			3,683			28,099			22,976
Benefits paid	(14,752		)	(13,574		)	(508		)	(619		)	(16,874		)	(3,683		)	(32,134		)	(17,876		)
Value of plan assets, December 31	$	443,962		$	404,335		$	—		$	—		$	—		$	—		$	443,962		$	404,335

Schedule of fair value of plan assets and the underfunded status

	Defined Benefit  Pension Plan						Post-Retirement  Medical Plan						Supplemental Executive Retirement Plan						Total
	December 31,						December 31,						December 31,						December 31,
	2014			2013			2014			2013			2014			2013			2014			2013
Under funded status at December 31	$	(139,118	)	$	(52,067	)	$	(12,782	)	$	(11,081	)	$	(55,832	)	$	(62,305	)	$	(207,732	)	$	(125,453	)

Schedule of amounts recognized in the consolidated balance sheets

The following table presents amounts recognized in the consolidated balance sheets for the Company’s Defined Benefit Pension, Post-Retirement Medical and Supplemental Executive Retirement plans:

	Defined Benefit  Pension Plan						Post-Retirement  Medical Plan						Supplemental Executive Retirement Plan						Total
	December 31,						December 31,						December 31,						December 31,
	2014			2013			2014			2013			2014			2013			2014			2013
Amounts recognized in consolidated balance sheets:
Other liabilities	$	(139,118	)	$	(52,067	)	$	(12,782	)	$	(11,081	)	$	(55,832	)	$	(62,305	)	$	(207,732	)	$	(125,453	)
Accumulated other comprehensive income (loss)	(165,652		)	(69,564		)	14,390			13,885			(11,990		)	(11,687		)	(163,252		)	(67,366		)

Schedule of amounts recognized in AOCI that have not yet been recognized as components of net periodic benefit costs

The following table provides information regarding amounts in AOCI that have not yet been recognized as components of net periodic benefit cost at December 31, 2014:

	Defined Benefit  Pension Plan						Post-Retirement  Medical Plan				Supplemental Executive Retirement Plan						Total
	Gross			Net of tax			Gross		Net of tax		Gross			Net of tax			Gross			Net of tax
Net gain (loss)	$	(165,639	)	$	(107,665	)	$	10,686	$	6,946	$	(8,856	)	$	(5,756	)	$	(163,809	)	$	(106,475	)
Net prior service (cost) credit	(13		)	(8		)	3,704		2,408		(3,134		)	(2,037		)	557			363
	$	(165,652	)	$	(107,673	)	$	14,390	$	9,354	$	(11,990	)	$	(7,793	)	$	(163,252	)	$	(106,112	)

Schedule of information regarding amounts in AOCI that are expected to be recognized as components of net periodic benefit costs during the next fiscal year

The following table provides information regarding amounts in AOCI that are expected to be recognized as components of net periodic benefit costs during the year ended December 31, 2015:

	Defined Benefit  Pension Plan						Post-Retirement  Medical Plan				Supplemental Executive Retirement Plan						Total
	Gross			Net of tax			Gross		Net of tax		Gross			Net of tax			Gross			Net of tax
Net gain (loss)	$	(12,023	)	$	(7,815	)	$	606	$	394	$	(663	)	$	(431	)	$	(12,080	)	$	(7,852	)
Prior service (cost) credit	(13		)	(8		)	1,669		1,085		(933		)	(606		)	723			471
	$	(12,036	)	$	(7,823	)	$	2,275	$	1,479	$	(1,596	)	$	(1,037	)	$	(11,357	)	$	(7,381	)

Schedule of expected benefit payments

The expected benefit payments for the Company’s Defined Benefit Pension, Post-Retirement Medical and Supplemental Executive Retirement plans for the years indicated are as follows:

	Defined Benefit Pension Plan		Post-Retirement Medical Plan		Supplemental Executive Retirement Plan
2015	$	15,670	$	606	$	4,874
2016	17,102		547		3,322
2017	18,192		556		3,306
2018	19,891		569		2,834
2019	21,285		625		2,518
2020 through 2024	135,763		4,171		15,883

Schedule of net periodic (benefit) cost

Net periodic (benefit) cost of the Defined Benefit Pension, Post-Retirement Medical and Supplemental Executive Retirement plans included in general insurance expenses in the accompanying consolidated statements of income includes the following components:

	Defined Benefit Pension Plan
	Year Ended December 31,
	2014			2013			2012
Components of net periodic cost:
Service cost	$	4,952		$	5,527		$	4,350
Interest cost	23,068			20,897			20,945
Expected return on plan assets	(29,288		)	(24,499		)	(21,797		)
Amortization of unrecognized prior service cost	51			51			51
Amortization of loss from earlier periods	2,898			16,001			9,941
Net periodic cost	$	1,681		$	17,977		$	13,490

	Post-Retirement Medical Plan
	Year Ended December 31,
	2014			2013			2012
Components of net periodic benefit:
Service cost	$	985		$	947		$	817
Interest cost	574			512			569
Amortization of unrecognized prior service benefit	(1,706		)	(1,650		)	(1,650		)
Amortization of gain from earlier periods	(450		)	(348		)	(455		)
Net periodic benefit	$	(597	)	$	(539	)	$	(719	)

	Supplemental Executive Retirement Plan
	Year Ended December 31,
	2014		2013		2012
Components of net periodic cost:
Service cost	$	586	$	1,002	$	991
Interest cost	2,528		2,548		2,912
Amortization of unrecognized prior service cost	4,844		933		934
Amortization of loss from earlier periods	282		1,299		637
Settlement	1,857		—		—
Net periodic cost	$	10,097	$	5,782	$	5,474

Schedule of weighted average interest rate assumptions used in determining benefit obligations

The following tables present the assumptions used in determining benefit obligations of the Defined Benefit Pension, Post-Retirement Medical and the Supplemental Executive Retirement plans:

	Defined Benefit Pension Plan
	December 31,
	2014		2013
Discount rate	4.17	%	5.11	%
Rate of compensation increase	4.47	%	4.47	%

	Post-Retirement Medical Plan
	December 31,
	2014		2013
Discount rate	3.94	%	4.83	%
Initial health care cost trend	6.50	%	7.00	%
Ultimate health care cost trend	5.00	%	5.00	%
Year ultimate trend is reached	2018		2018

	Supplemental Executive Retirement Plan
	December 31,
	2014		2013
Discount rate	3.99	%	4.61	%
Rate of compensation increase	4.00	%	4.00	%

Schedule of weighted average interest rate assumptions used in determining the net periodic (benefit) cost

The following tables present the assumptions used in determining the net periodic (benefit) cost of the Defined Benefit Pension, Post-Retirement Medical and the Supplemental Executive Retirement plans:

	Defined Benefit Pension Plan
	Year Ended December 31,
	2014		2013
Discount rate	5.11	%	4.19	%
Expected return on plan assets	7.25	%	7.25	%
Rate of compensation increase	4.47	%	3.14	%

	Post-Retirement Medical Plan
	Year Ended December 31,
	2014		2013
Discount rate	4.83	%	3.74	%
Initial health care cost trend	7.00	%	7.50	%
Ultimate health care cost trend	5.00	%	5.25	%
Year ultimate trend is reached	2018		2018

	Supplemental Executive Retirement Plan
	Year Ended December 31,
	2014		2013
Discount rate	4.61	%	3.79	%
Rate of compensation increase	4.00	%	4.00	%

Schedule of effect of one-percentage-point change in assumed healthcare cost trend rates

The following table presents the impact on the Post-Retirement Medical Plan that a one-percentage-point change in assumed health care cost trend rates would have on the following:

	One percentage point increase		One percentage point decrease
Increase (decrease) on total service and interest cost on components	$	254	$	(212	)
Increase (decrease) on post-retirement benefit obligation	1,722		(1,467		)

Schedule of investment of defined benefit pension plan assets

The following table presents how the Company’s Defined Benefit Pension Plan assets are invested:

	December 31,
	2014		2013
Equity securities	65	%	63	%
Debt securities	33	%	34	%
Other	2	%	3	%
Total	100	%	100	%

Schedule of defined benefit retirement plan assets measured at fair value on a recurring basis

The following tables present information about the Defined Benefit Retirement Plan’s assets measured at fair value on a recurring basis and indicates the fair value hierarchy of the valuation techniques utilized to determine such fair value:

	Defined benefit plan assets measured at fair value on a recurring basis
	December 31, 2014
	Quoted prices in active markets  for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
Common collective trust funds:
Equity index funds	$	—	$	93,415	$	—	$	93,415
Midcap index funds	—		90,159		—		90,159
World equity index funds	—		8,759		—		8,759
U.S. equity market funds	—		93,911		—		93,911
Total common collective trust funds	—		286,244		—		286,244
Fixed maturity investments:
U.S. government direct obligations and agencies	—		9,308		—		9,308
Obligations of U.S. states and their municipalities	—		18,838		—		18,838
Corporate debt securities	—		107,125		—		107,125
Asset-backed securities	—		8,444		—		8,444
Commercial mortgage-backed securities	—		3,048		—		3,048
Total fixed maturity investments	—		146,763		—		146,763
Preferred stock	310		—		—		310
Limited partnership investments	—		—		8,114		8,114
Money market funds	2,531		—		—		2,531
Total defined benefit plan assets	$	2,841	$	433,007	$	8,114	$	443,962

	Defined benefit plan assets measured at fair value on a recurring basis
	December 31, 2013
	Quoted prices in active markets  for identical assets (Level 1)		Significant other observable inputs (Level 2)		Significant unobservable inputs (Level 3)		Total
Common collective trust funds:
Equity index funds	$	—	$	82,440	$	—	$	82,440
Midcap index funds	—		82,674		—		82,674
World equity index funds	—		8,186		—		8,186
U.S. equity market funds	—		83,209		—		83,209
Total common collective trust funds	—		256,509		—		256,509
Fixed maturity investments:
U.S. government direct obligations and agencies	—		19,088		—		19,088
Obligations of U.S. states and their municipalities	—		14,973		—		14,973
Corporate debt securities	—		91,860		—		91,860
Asset-backed securities	—		7,902		—		7,902
Commercial mortgage-backed securities	—		2,647		—		2,647
Total fixed maturity investments	—		136,470		—		136,470
Preferred stock	700		—		—		700
Limited partnership investments	—		—		7,557		7,557
Money market funds	3,099		—		—		3,099
Total defined benefit plan assets	$	3,799	$	392,979	$	7,557	$	404,335

Schedule of defined benefit retirement plan assets measured at fair value on a recurring basis for which Level 3 inputs are utilized

The following tables present additional information about assets of the Defined Benefit Retirement Plan measured at fair value on a recurring basis and for which the Company has utilized Level 3 inputs to determine fair value:

	Fair value measurements using significant unobservable inputs (Level 3) limited partnership interest
	Year Ended December 31,
	2014			2013
Balance, January 1	$	7,557		$	6,485
Actual return on plan assets	510			853
Purchases	656			630
Issuances	(609		)	(411		)
Balance, December 31	$	8,114		$	7,557

Schedule of targets for the allocation of invested Defined Benefit Pension Plan assets

The following table presents the ranges the Company targets for the allocation of invested Defined Benefit Pension Plan assets at December 31, 2015:

	December 31, 2015
Equity securities	30	%
Debt securities	52	%
Other	18	%
Total	100	%