Share-Based Compensation (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award
Number of stock appreciation rights outstanding	0
Number of stock appreciation rights granted	0	0	0
Share-Based Compensation Information
Share-based Compensation Arrangement by Share-based Payment Award, Number of plans	4
Share-based compensation expense | $	$ 8,222	$ 7,314	$ 6,116
Excess Tax Benefit on Stock Plans | $	$ 859	$ 1,793	$ 5,178
Valuation assumptions used for the 2015, 2014 and 2013 grants
Expected volatility, minimum	32.00%	47.00%	51.00%
Expected volatiity, maximum	36.00%	50.00%	51.00%
Weighted-average expected volatility	36.00%	50.00%	51.00%
Expected dividend yield, minimum	1.10%	1.10%
Expected dividend yield, maximum	1.20%	1.30%
Expected dividend yield			1.60%
Weighted-average expected dividend yield	1.20%	1.30%	1.60%
Expected term, in years	5 years	6 years	6 years
Risk-free interest rate, minimum	1.40%	1.80%	0.90%
Risk-free interest rate, maximum	2.00%	2.00%	1.10%
Share-based Compensation Arrangement by Share-based Payment Award Additional Disclosures
Weighted-average remaining contractual life for options outstanding (in years)	6 years
Weighted-average remaining contractual life for options exercisable (in years)	5 years
Fair value of shares vested | $		$ 0
2010 Plan
Share-based Compensation Arrangement by Share-based Payment Award
Shares authorized for future awards (in shares)	1,500,000
Amended 2010 Plan
Share-based Compensation Arrangement by Share-based Payment Award
Shares authorized for future awards (in shares)	2,600,000
Shares reserved for issuance (in shares)	1,078,271
All Plans Excluding 2010 Plan
Share-based Compensation Arrangement by Share-based Payment Award
Shares reserved for issuance (in shares)	262,498
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award
Ratio of new awards that vest each year	one-third
Vesting period of new awards granted (in years)	3 years
Contractual term of new awards (in years)	10 years
Shares activity
Outstanding at beginning of year (in shares)	908,030
Granted (in shares)	177,020
Exercised (in shares)	(54,060)
Forfeited (in shares)	(10,814)
Expired (in shares)	(1,218)
Outstanding at end of year (in shares)	1,018,958	908,030
Exercisable at end of year (in shares)	756,470
Weighted-Average Exercise Price
Outstanding at beginning of year (in dollars per share) | $ / shares	$ 34.21
Granted (in dollars per share) | $ / shares	66.49
Exercised (in dollars per share) | $ / shares	31.03
Forfeited (in dollars per share) | $ / shares	59.22
Expired (in dollars per share) | $ / shares	60.67
Outstanding at end of year (in dollars per share) | $ / shares	39.69	$ 34.21
Exercisable at end of year | $ / shares	31.68
Share-based Compensation Arrangement by Share-based Payment Award Additional Disclosures
Weighted-average grant date fair value (in dollars per share) | $ / shares	$ 20.08	$ 26.93	$ 19.62
Total intrinsic value of stock options exercised | $	$ 1,702	$ 2,972	$ 15,641
Aggregate intrinsic value of options outstanding | $	19,260
Aggregate intrinsic value of options exercisable | $	18,926
Unrecognized compensation cost for nonvested options | $	$ 2,187
Compensation cost not yet recognized, weighted-average period for recognition (in years)	1 year 2 months 30 days
Restricted Share Awards
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period of new awards granted (in years)	3 years
Shares activity
Nonvested at beginning of year (in shares)	144,475
Granted (in shares)	23,048
Vested (in shares)	(24,245)
Forfeited (in shares)	(4,459)
Nonvested at end of year (in shares)	138,819	144,475
Weighted-Average Exercise Price
Nonvested at beginning of year (in dollars per share) | $ / shares	$ 40.51
Granted (in dollars per share) | $ / shares	66.33
Vested (in dollars per share) | $ / shares	43.47
Forfeited (in dollars per share) | $ / shares	55.96
Nonvested at end of year (in dollars per share) | $ / shares	$ 43.83	$ 40.51
Share-based Compensation Arrangement by Share-based Payment Award Additional Disclosures
Fair value of shares vested | $	$ 1,054	$ 827	643
Unrecognized compensation cost for nonvested options | $	$ 1,568
Compensation cost not yet recognized, weighted-average period for recognition (in years)	1 year 10 months
Performance Share Awards
Share-based Compensation Arrangement by Share-based Payment Award
Maximum increase in the number of shares of common stock a participant receives based on the achievement of performance goals (as a percent)	200.00%
Lowest potential number of shares of common stock that could be received based on the achievement level of performance goals	0
Shares activity
Nonvested at beginning of year (in shares)	152,555
Granted (in shares)	50,010
Vested (in shares)	(38,902)
Forfeited (in shares)	(22,289)
Nonvested at end of year (in shares)	141,374	152,555
Weighted-Average Exercise Price
Nonvested at beginning of year (in dollars per share) | $ / shares	$ 49.20
Granted (in dollars per share) | $ / shares	66.63
Vested (in dollars per share) | $ / shares	44.03
Forfeited (in dollars per share) | $ / shares	53.75
Nonvested at end of year (in dollars per share) | $ / shares	$ 56.07	$ 49.20
Share-based Compensation Arrangement by Share-based Payment Award Additional Disclosures
Fair value of shares vested | $	$ 1,713	$ 4,346	0
Unrecognized compensation cost for nonvested options | $	$ 2,660
Compensation cost not yet recognized, weighted-average period for recognition (in years)	1 year 8 months
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award
Vesting period of new awards granted (in years)	3 years
Shares activity
Nonvested at beginning of year (in shares)	16,549
Granted (in shares)	18,061
Vested (in shares)	(150)
Forfeited (in shares)	(1,814)
Nonvested at end of year (in shares)	32,646	16,549
Weighted-Average Exercise Price
Nonvested at beginning of year (in dollars per share) | $ / shares	$ 69.24
Granted (in dollars per share) | $ / shares	64.58
Vested (in dollars per share) | $ / shares	65.26
Forfeited (in dollars per share) | $ / shares	65.52
Nonvested at end of year (in dollars per share) | $ / shares	$ 66.89	$ 69.24
Share-based Compensation Arrangement by Share-based Payment Award Additional Disclosures
Fair value of shares vested | $	$ 10		0
Unrecognized compensation cost for nonvested options | $	$ 1,078
Compensation cost not yet recognized, weighted-average period for recognition (in years)	1 year 2 months
Share-Based Liabilities
Share-based Compensation Arrangement by Share-based Payment Award Additional Disclosures
Total share-based liabilities | $	$ 149	$ 139
Amounts paid out related to share-based liability awards | $	$ 53	$ 275	$ 3,134