Stock-based compensation (Tables)

The significant weighted average assumptions for the years ended December 31, 2018 and 2017 were as follows:

	2018			2017
Risk free interest rate		2.05	%		1.09	%
Expected option life (years)		1.2			1.0
Expected volatility		25.10	%		37.21	%
Expected dividend yield		2.62	%		2.41	%

A summary of the Company’s stock option activity for the year ended December 31, 2018 is as follows:

	Options			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)	Aggregate Intrinsic Value (1)
Outstanding at beginning of period		12,085		$	12.38
Granted		10,159			10.58
Exercised		(1,335	)		9.72
Forfeited/expired		(10,079	)		10.58
Outstanding as of December 31, 2018		10,830		$	12.69	2.05 years	$	-
Exercisable as of December 31, 2018		-		$	0.00	- years	$	-

(1)	The intrinsic value of a stock option represents the amount by which the fair value of the underlying stock, measured by reference to the closing price of the common shares of $ 11.66 on the Nasdaq Global Select Market on December 31, 2018, exceeds the exercise price of the option.

The following table summarizes the weighted average fair value of options at the date of grant and the intrinsic value of options exercised during the years ended December 31, 2018 and 2017:

	2018		2017
Options granted with an exercise price below market price on the date of grant:
Employees — preferred stock	$	3.27	$	4.11
Overall weighted average		3.27		4.11

Options granted with an exercise price at market price on the date of grant:
Management employees	$	-	$	-
Employees — common stock		3.19		3.23
Overall weighted average		3.19		3.23

Options granted with an exercise price above market price on the date of grant:
Management employees	$	-	$	-
Employees — preferred stock		-		-
Overall weighted average		-		-

Total intrinsic value of options exercised	$	4,379	$	8,942