Share-Based Payment Arrangements (Summary of Option Activity) (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate Intrinsic Value, Outstanding at Beginning | $	$ 3,734
Aggregate Intrinsic Value, Exercised/Released | $	3,270
Aggregate Intrinsic Value, Cancelled/Forfeited | $	$ 6
Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Outstanding at Beginning | shares	456,258
Number of Shares, Exercised/Released | shares	(256,611)
Number of Shares, Cancelled/Forfeited | shares	(538)
Number of Shares, Expired | shares	(689)
Number of Shares, Outstanding at Ending | shares	198,420
Number of Shares, Exercisable at Ending | shares	177,151
Weighted Average Exercise Price, Outstanding at Beginning | $ / shares	$ 35.91
Weighted Average Exercise Price, Exercised/Released | $ / shares	33.71
Weighted Average Exercise Price, Cancelled/Forfeited | $ / shares	32.09
Weighted Average Exercise Price, Expired | $ / shares	44.91
Weighted Average Exercise Price, Outstanding at Ending | $ / shares	38.74
Weighted Average Exercise Price, Exercisable at Ending | $ / shares	$ 39.83
Weighted Average Remaining Contractual Term (Years), Outstanding at Ending	2 years 10 months 28 days
Weighted Average Remaining Contractual Term (Years), Exercisable at Ending	2 years 7 months 21 days
Aggregate Intrinsic Value, Outstanding at Ending | $	$ 1,728
Aggregate Intrinsic Value, Exercisable at Ending | $	$ 1,392