Employee Benefit Plans (Details 7) (USD $)	12 Months Ended
	Dec. 31, 2013
Exercise price $7.48
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 7.48
Options outstanding:
Number of options (in shares)	391,343
Weighted average remaining contract life	5 years 3 months
Options exercisable:
Number of options (in shares)	183,316
Weighted average remaining term - vested	5 years 3 months
Exercise price $9.79
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 9.79
Options outstanding:
Number of options (in shares)	413,379
Weighted average remaining contract life	5 years
Options exercisable:
Number of options (in shares)	272,905
Weighted average remaining term - vested	5 years
Exercise price $9.86
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 9.86
Options outstanding:
Number of options (in shares)	213,106
Weighted average remaining contract life	2 years 3 months
Options exercisable:
Number of options (in shares)	213,106
Weighted average remaining term - vested	2 years 3 months
Exercise price $10.19
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 10.19
Options outstanding:
Number of options (in shares)	338,060
Weighted average remaining contract life	1 year 3 months
Options exercisable:
Number of options (in shares)	338,060
Weighted average remaining term - vested	1 year 3 months
Exercise price $11.12
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 11.12
Options outstanding:
Number of options (in shares)	345,618
Weighted average remaining contract life	4 years 3 months
Options exercisable:
Number of options (in shares)	345,618
Weighted average remaining term - vested	4 years 3 months
Exercise price $11.33
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 11.33
Options outstanding:
Number of options (in shares)	252,220
Weighted average remaining contract life	1 year
Options exercisable:
Number of options (in shares)	252,220
Weighted average remaining term - vested	1 year
Exercise price $11.49
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 11.49
Options outstanding:
Number of options (in shares)	482,244
Weighted average remaining contract life	6 years 3 months
Options exercisable:
Number of options (in shares)	174,501
Weighted average remaining term - vested	6 years 3 months
Exercise price $11.51
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 11.51
Options outstanding:
Number of options (in shares)	301,077
Weighted average remaining contract life	3 years 3 months
Options exercisable:
Number of options (in shares)	301,077
Weighted average remaining term - vested	3 years 3 months
Exercise price $11.70
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 11.70
Options outstanding:
Number of options (in shares)	549,955
Weighted average remaining contract life	8 years 6 months
Options exercisable:
Number of options (in shares)	91,257
Weighted average remaining term - vested	8 years 6 months
Exercise price $12.12
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 12.12
Options outstanding:
Number of options (in shares)	524,879
Weighted average remaining contract life	7 years 3 months
Options exercisable:
Number of options (in shares)	114,176
Weighted average remaining term - vested	7 years 3 months
Exercise price $12.17
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 12.17
Options outstanding:
Number of options (in shares)	21,500
Weighted average remaining contract life	7 years 6 months
Options exercisable:
Number of options (in shares)	71
Weighted average remaining term - vested	7 years 6 months
Exercise price $12.32
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 12.32
Options outstanding:
Number of options (in shares)	2,392,863
Weighted average remaining contract life	9 years 6 months
Options exercisable:
Number of options (in shares)	571,534
Weighted average remaining term - vested	7 years 6 months
Exercise price $12.44
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 12.44
Options outstanding:
Number of options (in shares)	585,550
Weighted average remaining contract life	9 years 6 months
Options exercisable:
Number of options (in shares)	54,280
Weighted average remaining term - vested	9 years 6 months
Exercise price $12.48
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 12.48
Options outstanding:
Number of options (in shares)	4,500
Weighted average remaining contract life	3 years 6 months
Options exercisable:
Number of options (in shares)	4,500
Weighted average remaining term - vested	3 years 6 months
$11.46
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 11.46
Options outstanding:
Number of options (in shares)	6,816,294
Weighted average remaining contract life	6 years 3 months 14 days
Options exercisable:
Number of options (in shares)	2,916,621
Weighted average remaining term - vested	4 years 4 months 20 days