Shareholders' Equity (Deficit): Dividends and Repurchase of Common Stock (Details) - USD ($)						9 Months Ended
	Aug. 16, 2017	Jul. 26, 2017	Jul. 19, 2017	Apr. 26, 2017	Jan. 25, 2017	Sep. 30, 2017
Repurchase of Common Stock
Aggregate purchase price of shares repurchased (in dollars)						$ 49,904,100
Dividends
Cash dividends declared and paid (in dollars per share)		$ 0.11		$ 0.11	$ 0.10
Tender Offer
Repurchase of Common Stock
Shares authorized for repurchase			400,000
Purchase of stock, price per share			$ 124.48
Number of shares repurchased	400,000
Aggregate purchase price of shares repurchased (in dollars)	$ 49,900,000
Common Stock Repurchase Program
Repurchase of Common Stock
Number of additional shares that can be repurchased						142,988