Deferred Compensation	12 Months Ended
Deferred Compensation	Dec. 31, 2016
Compensation Related Costs [Abstract]
Deferred Compensation	12. Deferred Compensation The Company sponsors deferred compensation plans that allow management employees to defer receipt of their annual bonuses and outside directors to defer receipt of their fees until retirement, departure from the Company or as otherwise elected. Compensation expense and the related deferred compensation obligation are recorded when the underlying compensation is earned. Over time, the deferred obligation may increase or decrease based on the performance results of investment options chosen by the plan participants. The investment options include Company common stock and a limited selection of mutual funds. The Company maintains sufficient shares of treasury stock to cover the equivalent number of shares that result from participants elections of the Company common stock investment option. As a result, the Company must periodically purchase its common shares in the open market. The Company purchases shares of the applicable mutual funds to fund the portion of its deferred compensation liabilities tied to such investments. Some plan distributions may be made in cash or Company common stock at the option of the participant. Other plan distributions can only be made in Company common stock. For deferred compensation obligations that may be settled in cash or Company common stock at the option of the participant, the Company must record appreciation in the market values of the investment choices made by participants as additional compensation expense. Conversely, declines in the market values of the investment choices reduce compensation expense. Increases and decreases of compensation expense that result from fluctuations in the underlying investments are recorded as part of operating expenses in the consolidated statements of income. The additional compensation expense or income resulting from the changes in the market values and earnings of the selected investment options was $16,805,000 expense in 2016, $6,500,000 expense in 2015 and $11,903,000 income in 2014. The increase in expense between 2016 and 2015 was primarily attributable to an increase in the market value of the Company’s common stock. The obligations that must be settled only in Company common stock are treated as equity instruments; therefore, fluctuations in the market price of the underlying Company stock do not affect earnings. The Company’s deferred compensation liability was $60,328,000 and $43,988,000 at December 31, 2016 and 2015, respectively.

The entire disclosure for compensation costs, including compensated absences accruals, compensated absences liability, deferred compensation arrangements and income statement compensation items. Deferred compensation arrangements may include a description of an arrangement with an individual employee, which is generally an employment contract between the entity and a selected officer or key employee containing a promise by the employer to pay certain amounts at designated future dates, usually including a period after retirement, upon compliance with stipulated requirements. This type of arrangement is distinguished from broader based employee benefit plans as it is usually tailored to the employee. Disclosure also typically includes the amount of related compensation expense recognized during the reporting period, the number of shares (units) issued during the period under such arrangements, and the carrying amount as of the balance sheet date of the related liability.