Stockholders' Equity and Equity Compensation (Tables)

6 Months Ended

Jun. 30, 2018

Equity [Abstract]

Summary of all stock award activity

A summary of the stock award activity is as follows:

	Six Months Ended June 30, 2018
	Stock Awards		Weighted Average Award Date Fair Value
Outstanding at December 31, 2017	1,428,878		$	21.53
Restricted stock units awarded	279,459		24.14
Performance stock units awarded	219,943		23.25
Restricted stock units distributed	(295,420	)	17.36
Performance stock units distributed	(296,909	)	21.55
Restricted stock units forfeited	(37,842	)	21.39
Performance stock units forfeited	(30,529	)	26.22
Outstanding at June 30, 2018	1,267,580		$	23.27

Summary of all deferred stock unit activity

A summary of deferred stock unit activity is as follows:

	Six Months Ended June 30, 2018
	Deferred Stock Units		Weighted Average Award Date Fair Value
Outstanding at December 31, 2017	269,977		$	20.14
Awarded	41,855		23.58
Distributed	(20,939	)	19.48
Outstanding at June 30, 2018	290,893		$	20.68

Financial data for stock option exercises

Financial data for stock option exercises are summarized as follows (in thousands):

	Six Months Ended June 30,
	2018		2017
Aggregate intrinsic value of outstanding stock options	$	403	$	349
Aggregate intrinsic value of exercisable stock options	403		349