Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2015

Compensation and Retirement Disclosure [Abstract]

Combined Activity in Corporations Defined Benefit Pension Plans

use a December 31 measurement date for our defined benefit plans. Combined activity in our defined benefit pension plans was as follows:

	2015			2014			2013
Change in benefit obligation:
Benefit obligation at beginning of year	$	199,637		$	163,876		$	178,158
Interest cost	8,210			8,002			7,341
Actuarial (gain) loss	(6,489		)	34,438			(15,333		)
Benefits paid	(7,218		)	(6,679		)	(6,290		)
Benefit obligation at end of year	194,140			199,637			163,876
Change in plan assets:
Fair value of plan assets at beginning of year	168,185			164,769			145,901
Actual return on plan assets	1,567			9,428			24,489
Employer contributions	736			667			669
Benefits paid	(7,218		)	(6,679		)	(6,290		)
Fair value of plan assets at end of year	163,270			168,185			164,769
Funded status of the plan at end of year and accrued (benefit) liability recognized	$	30,870		$	31,452		$	(893	)
Accumulated benefit obligation at end of year	$	194,140		$	199,637		$	163,876

Disaggregated Information Related to Corporations Defined Benefit Pension Plans

Certain disaggregated information related to our defined benefit pension plans as of year-end was as follows:

	Retirement Plan				Restoration Plan
	2015		2014		2015		2014
Projected benefit obligation	$	174,429	$	179,970	$	19,711	$	19,667
Accumulated benefit obligation	174,429		179,970		19,711		19,667
Fair value of plan assets	163,270		168,185		—		—
Funded status of the plan at end of year and accrued (benefit) liability recognized	11,159		11,785		19,711		19,667

Net Periodic Benefit Cost (Benefit)

The components of the combined net periodic cost (benefit) for our defined benefit pension plans were as follows:

	2015			2014			2013
Expected return on plan assets, net of expenses	$	(11,932	)	$	(12,514	)	$	(11,087	)
Interest cost on projected benefit obligation	8,210			8,002			7,341
Net amortization and deferral	6,995			2,687			6,558
Net periodic expense (benefit)	$	3,273		$	(1,825	)	$	2,812

Defined Benefit Pension Plans Recognized as Component of Other Comprehensive Income

Amounts related to our defined benefit pension plans recognized as a component of other comprehensive income were as follows:

	2015			2014			2013
Net actuarial gain (loss)	$	3,118		$	(34,837	)	$	35,293
Deferred tax (expense) benefit	(1,091		)	12,193			(12,353		)
Other comprehensive income (loss), net of tax	$	2,027		$	(22,644	)	$	22,940

Defined Benefit Pension Plans Not Recognized as Component of Combined Net Period Benefit Cost

expect to recognize approximately $6.2 million of the net actuarial loss reported in the following table as of December 31, 2015 as a component of net periodic benefit cost during 2016.

	2015			2014
Net actuarial loss	$	(71,920	)	$	(75,038	)
Deferred tax benefit	25,172			26,263
Amounts included in accumulated other comprehensive loss, net of tax	$	(46,748	)	$	(48,775	)

Weighted-Average Assumptions Used to Determine Benefit Obligations

The weighted-average assumptions used to determine the benefit obligations as of the end of the years indicated and the net periodic benefit cost for the years indicated are presented in the table below. Because the plans were frozen, increases in compensation are not considered after 2001.

	2015		2014		2013
Benefit obligations:
Discount rate	4.55	%	4.20	%	5.00	%
Net periodic benefit cost:
Discount rate	4.20	%	5.00	%	4.20	%
Expected return on plan assets	7.25		7.25		7.75

Fair Value of Plan Assets

The major categories of assets in our Retirement Plan as of year-end are presented in the following table. Assets are segregated by the level of the valuation inputs within the fair value hierarchy established by ASC Topic 820 “Fair Value Measurements and Disclosures,” utilized to measure fair value (see Note 18 - Fair Value Measurements). Our Restoration Plan is unfunded.

	2015		2014
Level 1:
Mutual funds	$	162,379	$	165,429
Cash and cash equivalents	322		1,447
Level 2:
Corporate bonds and notes	—		653
U.S. government agency securities	316		394
States and political subdivisions	253		262
Total fair value of plan assets	$	163,270	$	168,185

Expected Future Benefit Payments Related to Defined Benefit Plans

As of December 31, 2015, expected future benefit payments related to our defined benefit plans were as follows:

2016	$	12,729
2017	9,421
2018	9,911
2019	10,365
2020	10,816
2021 through 2025	58,848
	$	112,090

Summary of Activity in Corporation's Active Stock Plans

A combined summary of activity in our active stock plans is presented in the following table.

			Director Deferred Stock Units Outstanding		Non-Vested Stock Awards/Stock Units Outstanding				Stock Options Outstanding
	Available for Grant		Number of Units	Weighted- Average Grant-Date Fair Value	Number of Shares/Units		Weighted- Average Grant-Date Fair Value		Number of Shares		Weighted- Average Exercise Price
Balance at January 1, 2013	1,188,963		27,724	55.46	188,560		$	51.67	5,513,516		$	51.94
Authorized	2,293,660		—	—	—		—		—		—
Granted	(635,360	)	5,500	60.07	38,010		71.39		591,850		71.38
Stock options exercised	—		—	—	—		—		(1,319,786	)	52.02
Stock awards/units vested	—		—	—	(26,830	)	50.64		—		—
Forfeited/expired	46,890		—	—	—		—		(46,890	)	46.05
Balance at December 31, 2013	2,894,153		33,224	56.22	199,740		55.32		4,738,690		54.35
Authorized	—		—	—	—		—		—		—
Granted	(955,443	)	5,643	78.04	32,050		78.92		917,750		78.93
Stock options exercised	—		—	—	—		—		(560,291	)	52.04
Stock awards/units vested	—		—	—	(56,300	)	52.46		—		—
Forfeited/expired	66,267		—	—	—		—		(66,267	)	62.21
Balance at December 31, 2014	2,004,977		38,867	59.39	175,490		60.55		5,029,882		58.99
Authorized	515,000		—	—	—		—		—		—
Granted	(951,506	)	6,576	72.94	53,990		65.11		890,940		65.11
Stock options exercised	—		—	—	—		—		(287,326	)	51.70
Stock awards/units vested	—		—	—	(56,300	)	48.00		—		—
Forfeited/expired	21,256		—	—	—		—		(21,256	)	66.72
Balance at December 31, 2015	1,589,727		45,443	61.35	173,180		$	66.05	5,612,240		$	60.30

Options Outstanding and Exercisable

Other information regarding options outstanding and exercisable as of December 31, 2015 is as follows:

					Options Outstanding				Options Exercisable
Range of Exercise Prices					Number of Shares	Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life in Years	Number of Shares	Weighted- Average Exercise Price
$	45.01	to	$	50.00	898,753	$	48.27	4.53	898,753	$	48.27
50.01		to	55.00		2,065,524	52.74		4.78	1,885,777	52.58
55.01		to	60.00		296,150	57.63		0.89	296,150	57.63
65.01		to	70.00		890,940	65.11		9.83	—	—
70.01		to	75.00		566,123	71.38		7.77	280,988	71.38
75.01		to	80.00		894,750	78.94		8.74	223,689	78.94
			Total		5,612,240	60.30		6.27	3,585,357	55.03

Shares Issued in Connection With Stock Compensation Awards

Shares issued in connection with stock compensation awards are issued from available treasury shares. If no treasury shares are available, new shares are issued from available authorized shares. Shares issued in connection with stock compensation awards along with other related information were as follows:

	2015		2014		2013
New shares issued from available authorized shares	—		—		153,275
Issued from available treasury stock	337,056		601,851		1,179,551
Total	337,056		601,851		1,332,826
Proceeds from stock option exercises	$	14,853	$	29,158	$	68,653
Intrinsic value of stock options exercised	5,766		13,714		20,506
Fair value of stock awards/units vested	3,728		4,346		1,918

Stock-Based Compensation Expense

Stock-based compensation expense and the related income tax benefit was as follows:

	2015		2014		2013
Stock options	$	9,660	$	9,142	$	8,814
Non-vested stock awards/stock units	2,597		2,920		2,819
Deferred stock-units	480		441		330
Total	$	12,737	$	12,503	$	11,963
Income tax benefit	$	4,458	$	4,376	$	4,187

Unrecognized Stock-Based Compensation Expense

Unrecognized stock-based compensation expense at December 31, 2015 was as follows:

Stock options	$	21,245
Non-vested stock awards/stock units	3,355
Total	$	24,600

Assumptions Used to Determine The Fair Value of Options Granted

The assumptions used to determine the fair value of options granted are detailed in the table below.

	2015		2014		2013
Weighted-average risk-free interest rate	2.05	%	2.33	%	2.65	%
Dividend yield	3.02		2.71		2.92
Weighted-average expected market price volatility	26.48		26.66		24.20
Weighted-average expected term	5.7 years		7.1 years		6.7 years