Shareholders' Equity and Dividends (Schedule of Quarterly Dividends Declared and Paid) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Dividends Payable [Line Items]
Dividends declared (usd per share)	$ 4.74	$ 0.2	$ 0.52
Quarterly Dividend [Member]
Dividends Payable [Line Items]
Dividends declared (usd per share)	$ 0.40	$ 0.2	$ 0.52
Dividends, common stock	$ 27,636	$ 13,754	$ 35,223