Condensed Consolidated Statement Of Shareholders' Equity (Parenthetical) - $ / shares		3 Months Ended						9 Months Ended
	Jan. 02, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Sep. 30, 2017	Sep. 30, 2016
Regular Cash Dividend
Dividends declared per common share (usd per share)		$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.25	$ 0.75	$ 0.75
Special Cash Dividend
Dividends declared per common share (usd per share)	$ 5.77	$ 0.00			$ 0.00			$ 5.77	$ 0.00