Shareholders' Equity (Common Stock Repurchases) (Details) - Share Repurchase Plans [Member] - USD ($) shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Equity, Class of Treasury Stock [Line Items]
Shares of common stock repurchased	40	301	334	545
Total cost of common stock repurchased	$ 18,885	$ 102,511	$ 115,300	$ 207,159

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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