Lines of Credit	3 Months Ended
Mar. 31, 2017
Line of Credit Facility [Abstract]
Lines of Credit	Line of Credit The Company has a five-year $300,000 Credit Agreement (the Credit Facility) with Wells Fargo Bank, National Association, and a syndicate of other lenders. The Credit Facility is scheduled to expire in June 2021, at which time any aggregate principal amount of loans outstanding becomes payable in full. Any borrowings made under the Credit Facility will accrue interest at rates that, at the Company's option, are based on a base rate (the Base Rate) plus a premium that can range from 0.25 percent to 1.00 percent or the London InterBank Offered Rate (LIBOR) plus a premium that can range from 1.25 percent to 2.00 percent depending on the Company’s Leverage Ratio (a ratio of consolidated indebtedness to consolidated EBITDA for the four preceding fiscal quarters, all as defined in the related agreement). The Base Rate is defined as the highest of a) the Federal Funds Rate, as published by the Federal Reserve Bank of New York, plus 0.50 percent, b) the prime commercial lending rate of Wells Fargo, c) the applicable LIBOR plus 1.00 percent, or d) 0 percent. The Company also pays quarterly commitment fees based on the unused portion of the Credit Facility. The quarterly fees for the Credit Facility can range from 0.15 percent of the amount of the unused portion to 0.30 percent, depending on the Company’s Leverage Ratio. Certain wholly-owned subsidiaries of the Company have guaranteed the obligations of the Company under the agreement. The aggregate amount of the Credit Facility may be increased by an additional $100,000 under certain conditions set forth in the agreement. The Credit Facility contains covenants that restrict the ability of the Company to engage in mergers, consolidations, asset sales, investments, transactions with affiliates, or to incur liens, as defined in the agreement. In the event of a default under the Credit Facility, the Company would also be restricted from paying dividends on, or repurchasing, its common stock without the approval of the lenders. None of the covenants of the Credit Facility negatively affect the Company’s liquidity or capital resources. Upon the occurrence of certain financial or economic events, significant corporate events, or certain other events of default constituting an event of default under the Credit Facility, all loans outstanding may be declared immediately due and payable and all commitments under the agreement may be terminated. The Company had no borrowings under the Credit Facility at March 31, 2017. The Company was in compliance with all covenants of the Credit Facility during the three months ended March 31, 2017.

Line of Credit

The Company has a five-year $300,000 Credit Agreement (the Credit Facility) with Wells Fargo Bank, National Association, and a syndicate of other lenders. The Credit Facility is scheduled to expire in June 2021, at which time any aggregate principal amount of loans outstanding becomes payable in full. Any borrowings made under the Credit Facility will accrue interest at rates that, at the Company's option, are based on a base rate (the Base Rate) plus a premium that can range from 0.25 percent to 1.00 percent or the London InterBank Offered Rate (LIBOR) plus a premium that can range from 1.25 percent to 2.00 percent depending on the Company’s Leverage Ratio (a ratio of consolidated indebtedness to consolidated EBITDA for the four preceding fiscal quarters, all as defined in the related agreement). The Base Rate is defined as the highest of a) the Federal Funds Rate, as published by the Federal Reserve Bank of New York, plus 0.50 percent, b) the prime commercial lending rate of Wells Fargo, c) the applicable LIBOR plus 1.00 percent, or d) 0 percent. The Company also pays quarterly commitment fees based on the unused portion of the Credit Facility. The quarterly fees for the Credit Facility can range from 0.15 percent of the amount of the unused portion to 0.30 percent, depending on the Company’s Leverage Ratio. Certain wholly-owned subsidiaries of the Company have guaranteed the obligations of the Company under the agreement. The aggregate amount of the Credit Facility may be increased by an additional $100,000 under certain conditions set forth in the agreement.

The Credit Facility contains covenants that restrict the ability of the Company to engage in mergers, consolidations, asset sales, investments, transactions with affiliates, or to incur liens, as defined in the agreement. In the event of a default under the Credit Facility, the Company would also be restricted from paying dividends on, or repurchasing, its common stock without the approval of the lenders. None of the covenants of the Credit Facility negatively affect the Company’s liquidity or capital resources. Upon the occurrence of certain financial or economic events, significant corporate events, or certain other events of default constituting an event of default under the Credit Facility, all loans outstanding may be declared immediately due and payable and all commitments under the agreement may be terminated. The Company had no borrowings under the Credit Facility at March 31, 2017. The Company was in compliance with all covenants of the Credit Facility during the three months ended March 31, 2017.