Shareholders' Equity - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) defined_benefit_plan shares	Dec. 31, 2015 USD ($) shares	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Equity [Abstract]
Common shares authorized (shares) | shares	100,000,000	100,000,000
Authorized preferred stock (shares) | shares		50,000,000
Authorization common shares for the issuance under incentive compensation plans (shares) | shares	2,200,000
Number of shares available for grant (shares) | shares	700,000
Dividends declared	$ 315,000	$ 119,900	$ 220,500
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity attributable to parent	1,798,702	1,958,354	$ 2,157,944	$ 2,394,414
Total authorizations which remain available for use (shares)	$ 109,600
Number of defined benefit plans assumed in acquisition | defined_benefit_plan	2
Loss related to unrecognized changes in defined benefit plan liabilities	$ 1,000	1,000
Impairment losses in accumulated other comprehensive income	$ 300	2,000
AOCI losses unrecognized changes in defined benefit plan liabilities, net		$ 1,000
Percentage of income before income taxes included in expected income tax expense (percent)	35.00%	35.00%	35.00%
Retained Earnings, Unappropriated
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity attributable to parent	$ 441,000