Stock Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2016

Stock Compensation Plans

Summary of status and activity of employee and non-employee directors' nonvested stock awards

		Weighted-			Weighted-			Weighted-
		Average		ROC	Average		TSR	Average
	Restricted	Grant Date		Performance	Grant Date		Performance	Grant Date
	Stock	Fair Value		Stock	Fair Value		Stock	Fair Value
	Awards	(per share)		Awards (a)	(per share)		Awards (a)	(per share)
Nonvested as of  January 1, 2016	204,689	$	20.28	76,942	$	19.33	68,505	$	21.74
Granted	159,938		14.65	35,719		13.76	50,880		9.66
Vested	(103,152)		19.56	—		—	(22,248)		21.92
Forfeited	(10,935)		19.43	(32,713)		17.56	(4,093)		21.79
Nonvested as of December 31, 2016	250,540	$	17.02	79,948	$	17.56	93,044	$	15.09

(a) The number of shares shown for the performance stock awards is based on the target number of share awards.

Employee stock options

Stock Compensation Plans

Summary of status and activity of stock options

				Weighted-
		Weighted-		Average
		Average		Remaining
		Exercise Price		Contractual Term	Aggregate
Employee stock options:	Shares	(per share)		(in years)	Intrinsic Value
Outstanding as of January 1, 2016	1,252,136	$	19.08	5.01	$	645
Granted	508,999		14.06
Exercised	(13,574)		9.10
Forfeited	(17,907)		17.91
Expired	(62,852)		18.33
Outstanding as of December 31, 2016	1,666,802	$	17.67	4.69	$	1,993
Vested and expected to vest as of December 31, 2016	1,666,802	$	17.67	4.69	$	1,993
Exercisable as of December 31, 2016	974,977	$	18.87	3.85	$	476

Schedule of assumptions used to calculate fair values of employee stock option grants

	Year Ended December 31
	2016			2015			2014
Weighted-average grant date fair value per stock option	$	3.11		$	3.30		$	4.48
Expected dividend yield		1.10	%		0.96	%		0.00	%
Expected volatility		29	%		19	%		21 - 22	%
Risk-free interest rates		1.04	%		1.48	%		1.51 - 1.73	%
Expected lives of options		4	years		4	years		4	years

Total Stockholder Return | Performance stock awards

Stock Compensation Plans

Schedule of significant assumptions used for performance stock awards

	Year Ended December 31
	2016		2015		2014
Dividend yield	1.10	%	0.96	%	0.00	%
Expected volatility	26.8	%	25.9	%	31.5	%
Risk-free interest rates	0.83	%	0.93	%	0.68	%
Performance period	3	years	3	years	3	years

Directors | Non employee stock options

Stock Compensation Plans

Summary of status and activity of stock options

				Weighted-
		Weighted-		Average
		Average		Remaining
		Exercise Price		Contractual Term	Aggregate
Non-employee director stock options:	Shares	(per share)		(in years)	Intrinsic Value
Outstanding as of January 1, 2016	39,885	$	6.99	0.81	$	379
Granted	—		—
Exercised	(22,320)		5.90
Forfeited	—		—
Expired	—		—
Outstanding as of December 31, 2016	17,565	$	8.37	0.42	$	154
Vested as of December 31, 2016	17,565	$	8.37	0.42	$	154
Exercisable as of December 31, 2016	17,565	$	8.37	0.42	$	154