Equity (Details 3) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Employee Stock Option [Member]
Stock Based Compensation Plans
Options granted (in shares)	0	15,000
Option exercised (in shares)	0	10,000
Options granted (in dollars per share)		$ 38.43
Vesting period		3 years
Value of options exercised		$ 238,000
Market value of options on the date of exercise		390,000
Options outstanding at end of the period (in shares)	43,334
Options exercisable at end of the period (in shares)	33,334
Compensation expense related to the vesting of stock awards	4,000	1,000
Remaining compensation expense to be recognized related to the future service period
2015	11,000
2016	15,000
2017	2,000
Employee Stock Option [Member] | Vesting Through December 31 2015 [Member]
Stock Based Compensation Plans
Options scheduled to vest (in shares)	0
Employee Stock Option [Member] | Vesting Through December 31 2016 [Member]
Stock Based Compensation Plans
Options scheduled to vest (in shares)	5,000
Employee Stock Option [Member] | Vesting Through December 31 2017 [Member]
Stock Based Compensation Plans
Options scheduled to vest (in shares)	5,000
Employee Stock Option [Member] | Vesting Beyond 2017 [Member]
Stock Based Compensation Plans
Options scheduled to vest (in shares)	0
Restricted Stock [Member]
Stock Based Compensation Plans
Compensation expense related to the vesting of stock awards	978,000	665,000
Remaining compensation expense to be recognized related to the future service period
2015	2,648,000
2016	2,227,000
2017	1,162,000
2018	$ 81,000
Restricted stock activity
Number of shares cancelled (in shares)	640
Granted (in shares)	65,750	62,000
Outstanding (in shares)	255,815
Restricted Stock [Member] | Vesting Through December 31 2015 [Member]
Restricted stock activity
Expected to vest (in shares)	94,168
Restricted Stock [Member] | Vesting Through December 31 2016 [Member]
Restricted stock activity
Expected to vest (in shares)	88,360
Restricted Stock [Member] | Vesting Through December 31 2017 [Member]
Restricted stock activity
Expected to vest (in shares)	51,367
Restricted Stock [Member] | Vesting Through December 31, 2018 [Member]
Restricted stock activity
Expected to vest (in shares)	21,920
Restricted Stock [Member] | Vesting Beyond 2018 [Member]
Restricted stock activity
Expected to vest (in shares)	0
Restricted Stock [Member] | Grant Date Price 44.45 [Member] | Vesting over Three Year Period from Grant Date [Member]
Stock Based Compensation Plans
Vesting period	3 years
Restricted stock activity
Granted (in shares)	65,750
Price per share	$ 44.45
Restricted Stock [Member] | Grant Date Price 36.81 [Member] | Vesting over Three Year Period from Grant Date [Member]
Stock Based Compensation Plans
Vesting period		3 years
Restricted stock activity
Granted (in shares)		59,000
Price per share		$ 36.81
Restricted Stock [Member] | Grant Date Price 38.43 [Member] | Vesting over Three Year Period from Grant Date [Member]
Stock Based Compensation Plans
Vesting period		3 years
Restricted stock activity
Granted (in shares)		3,000
Price per share		$ 38.43