Subsequent Events (Details) - $ / shares		1 Months Ended
	Apr. 25, 2017	Jan. 31, 2017
Subsequent Events:
Dividend declared (in dollars per share)		$ 1.40
Subsequent events
Subsequent Events:
Dividend declared (in dollars per share)	$ 1.50
Dividend declared, date	Apr. 25, 2017
Dividend payable, date	Jun. 10, 2017
Shareholders of record, date	May 10, 2017
Dividend per share increase (in dollars per share)	$ 0.10
Dividend per share increase (as a percent)	7.00%